| Aa Rchb. f. | | a | | Aa Rchb. f. | | Orchidaceae |
| Abaxianthus M. A. Clem. & D. L. Jones | Dendrobium Sw. | | | Abaxianthus M. A. Clem. & D. L. Jones | Dendrobium Sw. | Orchidaceae |
| Abdominea J. J. Sm. | Robiquetia Gaudich. | | | Abdominea J. J. Sm. | Robiquetia Gaudich. | Orchidaceae |
| Abola Lindl. | Caucaea Schltr. | | | Abola Lindl. | Caucaea Schltr. | Orchidaceae |
| Acacallis Lindl. | Aganisia Lindl. | | | Acacallis Lindl. | Aganisia Lindl. | Orchidaceae |
| Acampe Lindl. | | a | | Acampe Lindl. | | Orchidaceae |
| Acanthephippium Blume | | a | | Acanthephippium Blume | | Orchidaceae |
| Acanthoglossum Blume | Pholidota Lindl. ex Hook. | | | Acanthoglossum Blume | Pholidota Lindl. ex Hook. | Orchidaceae |
| Acanthophippium Blume, orth. var. | Acanthephippium Blume | | | Acanthophippium Blume, orth. var. | Acanthephippium Blume | Orchidaceae |
| Aceras R. Br. | Orchis L. | | | Aceras R. Br. | Orchis L. | Orchidaceae |
| Aceratorchis Schltr. | | a | | Aceratorchis Schltr. | | Orchidaceae |
| Achlydosa M. A. Clem. & D. L. Jones | | a | | Achlydosa M. A. Clem. & D. L. Jones | | Orchidaceae |
| Achlydosa M. A. Clem. & D. L. Jones | | a | | Achlydosa M. A. Clem. & D. L. Jones | | Orchidaceae |
| Achroanthes Raf. | Malaxis Sol. ex Sw. | | | Achroanthes Raf. | Malaxis Sol. ex Sw. | Orchidaceae |
| Acianthera Scheidw. | Pleurothallis R. Br. | | | Acianthera Scheidw. | Pleurothallis R. Br. | Orchidaceae |
| Acianthopsis M. A. Clem. & D. L. Jones | | a | | Acianthopsis M. A. Clem. & D. L. Jones | | Orchidaceae |
| Acianthus R. Br. | | a | | Acianthus R. Br. | | Orchidaceae |
| Acineta Lindl. | | a | | Acineta Lindl. | | Orchidaceae |
| Acinopetala Luer | Masdevallia Ruiz & Pav. | | | Acinopetala Luer | Masdevallia Ruiz & Pav. | Orchidaceae |
| ×Aciopea Gav.-Correa | | a | | Aciopea Gav.-Correa | | Orchidaceae |
| Ackermania Dodson & R. Escobar | Benzingia Dodson | | | Ackermania Dodson & R. Escobar | Benzingia Dodson | Orchidaceae |
| Aclinia Griff. | Dendrobium Sw. | | | Aclinia Griff. | Dendrobium Sw. | Orchidaceae |
| Acoidium Lindl. | Trichocentrum Poepp. & Endl. | | | Acoidium Lindl. | Trichocentrum Poepp. & Endl. | Orchidaceae |
| Acoridium Nees & Meyen | Dendrochilum Blume | | | Acoridium Nees & Meyen | Dendrochilum Blume | Orchidaceae |
| Acostaea Schltr. | | a | | Acostaea Schltr. | | Orchidaceae |
| Acraea Lindl. | Pterichis Lindl. | | | Acraea Lindl. | Pterichis Lindl. | Orchidaceae |
| Acriopsis Blume | | a | | Acriopsis Blume | | Orchidaceae |
| Acrochaene Lindl. | Bulbophyllum Thouars | | | Acrochaene Lindl. | Bulbophyllum Thouars | Orchidaceae |
| Acrolophia Pfitzer | | a | | Acrolophia Pfitzer | | Orchidaceae |
| Acronia C. Presl | Pleurothallis R. Br. | | | Acronia C. Presl | Pleurothallis R. Br. | Orchidaceae |
| Acropera Lindl. | Gongora Ruiz & Pav. | | | Acropera Lindl. | Gongora Ruiz & Pav. | Orchidaceae |
| Acrorchis Dressler | | a | | Acrorchis Dressler | | Orchidaceae |
| Acrostylia Frapp. ex Cordem. | Cynorkis Thouars | | | Acrostylia Frapp. ex Cordem. | Cynorkis Thouars | Orchidaceae |
| Ada Lindl. | Brassia R. Br. | | | Ada Lindl. | Brassia R. Br. | Orchidaceae |
| Adactylus Rolfe | Apostasia Blume | | | Adactylus Rolfe | Apostasia Blume | Orchidaceae |
| Adamanthus Szlach. | Camaridium Lindl. | | | Adamanthus Szlach. | Camaridium Lindl. | Orchidaceae |
| Adamantinia C. van den Berg & C. N. Gonç. | | a | | Adamantinia C. van den Berg & C. N. Gonç. | | Orchidaceae |
| Adelopetalum Fitzg. | Bulbophyllum Thouars | | | Adelopetalum Fitzg. | Bulbophyllum Thouars | Orchidaceae |
| Adeneleuterophora Barb. Rodr. | Elleanthus C. Presl | | | Adeneleuterophora Barb. Rodr. | Elleanthus C. Presl | Orchidaceae |
| Adenochilus Hook. f. | | a | | Adenochilus Hook. f. | | Orchidaceae |
| Adenoncos Blume | | a | | Adenoncos Blume | | Orchidaceae |
| Adenostylis Blume | Zeuxine Lindl. | | | Adenostylis Blume | Zeuxine Lindl. | Orchidaceae |
| Adnula Raf. | Pelexia Poit. ex Lindl. | | | Adnula Raf. | Pelexia Poit. ex Lindl. | Orchidaceae |
| Adrorhizon Hook. f. | | a | | Adrorhizon Hook. f. | | Orchidaceae |
| Aenhenrya Gopalan | | a | | Aenhenrya Gopalan | | Orchidaceae |
| Aeonia Lindl., orth. var. | Oeonia Lindl. | | | Aeonia Lindl., orth. var. | Oeonia Lindl. | Orchidaceae |
| Aerangis Rchb. f. | | a | | Aerangis Rchb. f. | | Orchidaceae |
| Aeranthes Lindl. | | a | | Aeranthes Lindl. | | Orchidaceae |
| Aeranthus Lindl. ex Spreng., orth. var. | Aeranthes Lindl. | | | Aeranthus Lindl. ex Spreng., orth. var. | Aeranthes Lindl. | Orchidaceae |
| Aerides Lour. | | a | | Aerides Lour. | | Orchidaceae |
| Aeridium Salisb. | Aerides Lour. | | | Aeridium Salisb. | Aerides Lour. | Orchidaceae |
| Aeridostachya (Hook. f.) Brieger | Eria Lindl. | | | Aeridostachya (Hook. f.) Brieger | Eria Lindl. | Orchidaceae |
| Aerobion Kaempf. ex Spreng. | Angraecum Bory | | | Aerobion Kaempf. ex Spreng. | Angraecum Bory | Orchidaceae |
| Aetheorhyncha Dressler | | a | | Aetheorhyncha Dressler | | Orchidaceae |
| Aetheria Blume ex Endl. | Stenorrhynchos Rich. ex Spreng. | | | Aetheria Blume ex Endl. | Stenorrhynchos Rich. ex Spreng. | Orchidaceae |
| Afropectinariella M. Simo & Stévart | | a | | Afropectinariella M. Simo & Stévart | | Orchidaceae |
| Afrorchis Szlach. | | a | | Afrorchis Szlach. | | Orchidaceae |
| Aganisia Lindl. | | a | | Aganisia Lindl. | | Orchidaceae |
| Aggeianthus Wight | Porpax Lindl. | | | Aggeianthus Wight | Porpax Lindl. | Orchidaceae |
| Aglossorhyncha Schltr., orth. var. | Aglossorrhyncha Schltr. | | | Aglossorhyncha Schltr., orth. var. | Aglossorrhyncha Schltr. | Orchidaceae |
| Aglossorrhyncha Schltr. | | a | | Aglossorrhyncha Schltr. | | Orchidaceae |
| Agrostophyllum Blume | | a | | Agrostophyllum Blume | | Orchidaceae |
| Alamania Lex. | | a | | Alamania Lex. | | Orchidaceae |
| Alaticaulia Luer | Masdevallia Ruiz & Pav. | | | Alaticaulia Luer | Masdevallia Ruiz & Pav. | Orchidaceae |
| Alatiglossum Baptista | Gomesa R. Br. | | | Alatiglossum Baptista | Gomesa R. Br. | Orchidaceae |
| Alatiliparis Marg. & Szlach. | Liparis Rich. | | | Alatiliparis Marg. & Szlach. | Liparis Rich. | Orchidaceae |
| ×Aliceara hort. | | a | | Aliceara hort. | | Orchidaceae |
| Alinorchis Szlach. | | a | | Alinorchis Szlach. | | Orchidaceae |
| Alipsa Hoffmanns. | Liparis Rich. | | | Alipsa Hoffmanns. | Liparis Rich. | Orchidaceae |
| Alismorkis Thouars | Calanthe R. Br. | | | Alismorkis Thouars | Calanthe R. Br. | Orchidaceae |
| Allochilus Gagnep. | Goodyera R. Br. | | | Allochilus Gagnep. | Goodyera R. Br. | Orchidaceae |
| Altensteinia Kunth | | a | | Altensteinia Kunth | | Orchidaceae |
| Alvisia Lindl. | Eria Lindl. | | | Alvisia Lindl. | Eria Lindl. | Orchidaceae |
| Amalia Rchb. | Laelia Lindl. | | | Amalia Rchb. | Laelia Lindl. | Orchidaceae |
| Amblostoma Scheidw. | Encyclia Hook. | | | Amblostoma Scheidw. | Encyclia Hook. | Orchidaceae |
| Amblyanthe Rauschert | Dendrobium Sw. | | | Amblyanthe Rauschert | Dendrobium Sw. | Orchidaceae |
| Amblyanthus (Schltr.) Brieger | Dendrobium Sw. | | | Amblyanthus (Schltr.) Brieger | Dendrobium Sw. | Orchidaceae |
| Amblyglottis Blume | Calanthe R. Br. | | | Amblyglottis Blume | Calanthe R. Br. | Orchidaceae |
| Ambrella H. Perrier | | a | | Ambrella H. Perrier | | Orchidaceae |
| Amerorchis Hultén | | a | | Amerorchis Hultén | | Orchidaceae |
| Amesia A. Nelson & J. F. Macbr. | Epipactis Zinn | | | Amesia A. Nelson & J. F. Macbr. | Epipactis Zinn | Orchidaceae |
| Amesiella Schltr. ex Garay | | a | | Amesiella Schltr. ex Garay | | Orchidaceae |
| Amitostigma Schltr. | | a | | Amitostigma Schltr. | | Orchidaceae |
| Amparoa Schltr. | Rhynchostele Rchb. f. | | | Amparoa Schltr. | Rhynchostele Rchb. f. | Orchidaceae |
| Amphigena Rolfe | Disa P. J. Bergius | | | Amphigena Rolfe | Disa P. J. Bergius | Orchidaceae |
| Amphiglottis Salisb. | Epidendrum L. | | | Amphiglottis Salisb. | Epidendrum L. | Orchidaceae |
| Amphorchis Thouars | Cynorkis Thouars | | | Amphorchis Thouars | Cynorkis Thouars | Orchidaceae |
| Ampliglossum Campacci | Gomesa R. Br. | | | Ampliglossum Campacci | Gomesa R. Br. | Orchidaceae |
| Anacamptis Rich. | | a | | Anacamptis Rich. | | Orchidaceae |
| Anacheilium Hoffmanns. | Prosthechea Knowles & Westc. | | | Anacheilium Hoffmanns. | Prosthechea Knowles & Westc. | Orchidaceae |
| Anathallis Barb. Rodr. | | a | | Anathallis Barb. Rodr. | | Orchidaceae |
| Ancistrochilus Rolfe | | a | | Ancistrochilus Rolfe | | Orchidaceae |
| Ancistrorhynchus Finet | | a | | Ancistrorhynchus Finet | | Orchidaceae |
| Andinia (Luer) Luer | | a | | Andinia (Luer) Luer | | Orchidaceae |
| Andinorchis Szlach. | Chaubardia Rchb. f. | | | Andinorchis Szlach. | Chaubardia Rchb. f. | Orchidaceae |
| Andreettaea Luer | Pleurothallis R. Br. | | | Andreettaea Luer | Pleurothallis R. Br. | Orchidaceae |
| Androchilus Liebm. ex Hartm. | Ponthieva R. Br. | | | Androchilus Liebm. ex Hartm. | Ponthieva R. Br. | Orchidaceae |
| Androcorys Schltr. | | a | | Androcorys Schltr. | | Orchidaceae |
| Androgyne Griff. | Panisea (Lindl.) Lindl. | | | Androgyne Griff. | Panisea (Lindl.) Lindl. | Orchidaceae |
| Anectochilus Blume, orth. var. | Anoectochilus Blume | | | Anectochilus Blume, orth. var. | Anoectochilus Blume | Orchidaceae |
| Anettea Szlach. & Mytnik | Oncidium Sw. | | | Anettea Szlach. & Mytnik | Oncidium Sw. | Orchidaceae |
| Angorchis Thouars | Angraecum Bory | | | Angorchis Thouars | Angraecum Bory | Orchidaceae |
| Angraecoides (Cordem.) Szlach. et al. | | a | | Angraecoides (Cordem.) Szlach. et al. | | Orchidaceae |
| Angraecopsis Kraenzl. | | a | | Angraecopsis Kraenzl. | | Orchidaceae |
| Angraecum Bory | | a | | Angraecum Bory | | Orchidaceae |
| Anguloa Ruiz & Pav. | | a | | Anguloa Ruiz & Pav. | | Orchidaceae |
| Ania Lindl. | | a | | Ania Lindl. | | Orchidaceae |
| Anisopetala (Kraenzl.) M. A. Clem. | Dendrobium Sw. | | | Anisopetala (Kraenzl.) M. A. Clem. | Dendrobium Sw. | Orchidaceae |
| Anisopetalon Hook. | Bulbophyllum Thouars | | | Anisopetalon Hook. | Bulbophyllum Thouars | Orchidaceae |
| Anistylis Raf. | Liparis Rich. | | | Anistylis Raf. | Liparis Rich. | Orchidaceae |
| Ankylocheilos Summerh. | Taeniophyllum Blume | | | Ankylocheilos Summerh. | Taeniophyllum Blume | Orchidaceae |
| Anneliesia Brieger & Lückel | Miltonia Lindl. | | | Anneliesia Brieger & Lückel | Miltonia Lindl. | Orchidaceae |
| Anocheile Hoffmanns. ex Rchb. | Epidendrum L. | | | Anocheile Hoffmanns. ex Rchb. | Epidendrum L. | Orchidaceae |
| Anochilus (Schltr.) Rolfe | Pterygodium Sw. | | | Anochilus (Schltr.) Rolfe | Pterygodium Sw. | Orchidaceae |
| Anoectochilus Blume | | a | | Anoectochilus Blume | | Orchidaceae |
| Anota Schltr. | Rhynchostylis Blume | | | Anota Schltr. | Rhynchostylis Blume | Orchidaceae |
| Ansellia Lindl. | | a | | Ansellia Lindl. | | Orchidaceae |
| Anteriorchis E. Klein & Strack | | a | | Anteriorchis E. Klein & Strack | | Orchidaceae |
| Anthereon Pridgeon & M. W. Chase | Pleurothallis R. Br. | | | Anthereon Pridgeon & M. W. Chase | Pleurothallis R. Br. | Orchidaceae |
| Anthericlis Raf. | Tipularia Nutt. | | | Anthericlis Raf. | Tipularia Nutt. | Orchidaceae |
| Anthogonium Wall. ex Lindl. | | a | | Anthogonium Wall. ex Lindl. | | Orchidaceae |
| Anthogyas Raf. | Bletia Ruiz & Pav. | | | Anthogyas Raf. | Bletia Ruiz & Pav. | Orchidaceae |
| Anthosiphon Schltr. | Cryptocentrum Benth. | | | Anthosiphon Schltr. | Cryptocentrum Benth. | Orchidaceae |
| Anticheirostylis Fitzg. | Prasophyllum R. Br. | | | Anticheirostylis Fitzg. | Prasophyllum R. Br. | Orchidaceae |
| Antilla (Luer) Luer | Pleurothallis R. Br. | | | Antilla (Luer) Luer | Pleurothallis R. Br. | Orchidaceae |
| Antillanorchis (C. Wright ex Griseb.) Garay | Tolumnia Raf. | | | Antillanorchis (C. Wright ex Griseb.) Garay | Tolumnia Raf. | Orchidaceae |
| Antillanorchis Garay | Tolumnia Raf. | | | Antillanorchis Garay | Tolumnia Raf. | Orchidaceae |
| Anzybas D. L. Jones & M. A. Clem. | | a | | Anzybas D. L. Jones & M. A. Clem. | | Orchidaceae |
| Aopla Lindl. | Herminium L. | | | Aopla Lindl. | Herminium L. | Orchidaceae |
| Aorchis Verm. | Galearis Raf. | | | Aorchis Verm. | Galearis Raf. | Orchidaceae |
| Apation Blume | Liparis Rich. | | | Apation Blume | Liparis Rich. | Orchidaceae |
| Apatostelis Garay | Stelis Sw. | | | Apatostelis Garay | Stelis Sw. | Orchidaceae |
| Apaturia Lindl. | Pachystoma Blume | | | Apaturia Lindl. | Pachystoma Blume | Orchidaceae |
| Apetalon Wight | Didymoplexis Griff. | | | Apetalon Wight | Didymoplexis Griff. | Orchidaceae |
| Aphyllorchis Blume | | a | | Aphyllorchis Blume | | Orchidaceae |
| Apista Blume | Podochilus Blume | | | Apista Blume | Podochilus Blume | Orchidaceae |
| Aplectrum (Nutt.) Torr. | | a | | Aplectrum (Nutt.) Torr. | | Orchidaceae |
| Aporopsis (Schltr.) M. A. Clem. & D. L. Jones | Dendrobium Sw. | | | Aporopsis (Schltr.) M. A. Clem. & D. L. Jones | Dendrobium Sw. | Orchidaceae |
| Aporostylis Rupp & Hatch | | a | | Aporostylis Rupp & Hatch | | Orchidaceae |
| Aporum Blume | Dendrobium Sw. | | | Aporum Blume | Dendrobium Sw. | Orchidaceae |
| Apostasia Blume | | a | | Apostasia Blume | | Orchidaceae |
| Appendicula Blume | | a | | Appendicula Blume | | Orchidaceae |
| Appendiculopsis (Schltr.) Szlach. | Agrostophyllum Blume | | | Appendiculopsis (Schltr.) Szlach. | Agrostophyllum Blume | Orchidaceae |
| Aracamunia Carnevali & I. Ramírez | | a | | Aracamunia Carnevali & I. Ramírez | | Orchidaceae |
| Arachnanthe Blume | Arachnis Blume | | | Arachnanthe Blume | Arachnis Blume | Orchidaceae |
| Arachnaria Szlach. | | a | | Arachnaria Szlach. | | Orchidaceae |
| Arachnis Blume | | a | | Arachnis Blume | | Orchidaceae |
| Arachnites F. W. Schmidt | Ophrys L. | | | Arachnites F. W. Schmidt | Ophrys L. | Orchidaceae |
| Arachnorchis D. L. Jones & M. A. Clem. | Caladenia R. Br. | | | Arachnorchis D. L. Jones & M. A. Clem. | Caladenia R. Br. | Orchidaceae |
| ×Aranda hort. | | a | | Aranda hort. | | Orchidaceae |
| ×Aranthera hort. | | a | | Aranthera hort. | | Orchidaceae |
| Archineottia S. C. Chen | Neottia Guett. | | | Archineottia S. C. Chen | Neottia Guett. | Orchidaceae |
| Archivea Christenson & Jenny | | a | | Archivea Christenson & Jenny | | Orchidaceae |
| Areldia Luer | Pleurothallis R. Br. | | | Areldia Luer | Pleurothallis R. Br. | Orchidaceae |
| Arethusa L. | | a | | Arethusa L. | | Orchidaceae |
| Argyrorchis Blume | Macodes (Blume) Lindl. | | | Argyrorchis Blume | Macodes (Blume) Lindl. | Orchidaceae |
| Arietinum Beck | Cypripedium L. | | | Arietinum Beck | Cypripedium L. | Orchidaceae |
| Arisanorchis Hayata | Cheirostylis Blume | | | Arisanorchis Hayata | Cheirostylis Blume | Orchidaceae |
| Aristotelea Lour. | Spiranthes Rich. | | | Aristotelea Lour. | Spiranthes Rich. | Orchidaceae |
| Armodorum Breda | Arachnis Blume | | | Armodorum Breda | Arachnis Blume | Orchidaceae |
| Arnedina Rchb. f. | Arundina Blume | | | Arnedina Rchb. f. | Arundina Blume | Orchidaceae |
| Arnottia A. Rich. | Cynorkis Thouars | | | Arnottia A. Rich. | Cynorkis Thouars | Orchidaceae |
| Arpophyllum Lex. | | a | | Arpophyllum Lex. | | Orchidaceae |
| Arrhynchium Lindl. & Paxton | Arachnis Blume | | | Arrhynchium Lindl. & Paxton | Arachnis Blume | Orchidaceae |
| Arthrochilium Beck | Epipactis Zinn | | | Arthrochilium Beck | Epipactis Zinn | Orchidaceae |
| Arthrochilus F. Muell. | | a | | Arthrochilus F. Muell. | | Orchidaceae |
| Arthrosia (Luer) Luer | Pleurothallis R. Br. | | | Arthrosia (Luer) Luer | Pleurothallis R. Br. | Orchidaceae |
| Artomeria Breda | Eria Lindl. | | | Artomeria Breda | Eria Lindl. | Orchidaceae |
| Artorima Dressler & G. E. Pollard | | a | | Artorima Dressler & G. E. Pollard | | Orchidaceae |
| Arundina Blume | | a | | Arundina Blume | | Orchidaceae |
| Asarca Lindl. | Chloraea Lindl. | | | Asarca Lindl. | Chloraea Lindl. | Orchidaceae |
| Ascidieria Seidenf. | | a | | Ascidieria Seidenf. | | Orchidaceae |
| ×Ascocenda hort. | | a | | Ascocenda hort. | | Orchidaceae |
| Ascocentropsis Senghas & Schildh. | Vanda Jones ex R. Br. | | | Ascocentropsis Senghas & Schildh. | Vanda Jones ex R. Br. | Orchidaceae |
| Ascocentrum Schltr. ex J. J. Sm. | Vanda Jones ex R. Br. | | | Ascocentrum Schltr. ex J. J. Sm. | Vanda Jones ex R. Br. | Orchidaceae |
| Ascochilopsis Carr | Grosourdya Rchb. f. | | | Ascochilopsis Carr | Grosourdya Rchb. f. | Orchidaceae |
| Ascochilus Ridl. | Grosourdya Rchb. f. | | | Ascochilus Ridl. | Grosourdya Rchb. f. | Orchidaceae |
| Ascoglossum Schltr. | Renanthera Lour. | | | Ascoglossum Schltr. | Renanthera Lour. | Orchidaceae |
| Ascolabium S. S. Ying | Holcoglossum Schltr. | | | Ascolabium S. S. Ying | Holcoglossum Schltr. | Orchidaceae |
| Ascotainia Ridl. | Tainia Blume | | | Ascotainia Ridl. | Tainia Blume | Orchidaceae |
| Aspasia Lindl. | | a | | Aspasia Lindl. | | Orchidaceae |
| Aspegrenia Poepp. & Endl. | Octomeria R. Br. | | | Aspegrenia Poepp. & Endl. | Octomeria R. Br. | Orchidaceae |
| Aspidogyne Garay | | a | | Aspidogyne Garay | | Orchidaceae |
| Aspla Rchb. | Herminium L. | | | Aspla Rchb. | Herminium L. | Orchidaceae |
| Astroglossus Rchb. ex Benth., nom. inval. | Telipogon Mutis ex Kunth | | | Astroglossus Rchb. ex Benth., nom. inval. | Telipogon Mutis ex Kunth | Orchidaceae |
| Ate Lindl. | Habenaria Willd. | | | Ate Lindl. | Habenaria Willd. | Orchidaceae |
| Auliza Small | Epidendrum L. | | | Auliza Small | Epidendrum L. | Orchidaceae |
| Aulosepalum Garay | | a | | Aulosepalum Garay | | Orchidaceae |
| Aulostylis Schltr. | Calanthe R. Br. | | | Aulostylis Schltr. | Calanthe R. Br. | Orchidaceae |
| Aurinocidium Romowicz & Szlach. | Grandiphyllum Docha Neto | | | Aurinocidium Romowicz & Szlach. | Grandiphyllum Docha Neto | Orchidaceae |
| Australorchis Brieger | Dendrobium Sw. | | | Australorchis Brieger | Dendrobium Sw. | Orchidaceae |
| Auxopus Schltr. | | a | | Auxopus Schltr. | | Orchidaceae |
| Aviceps Lindl. | Satyrium Sw. | | | Aviceps Lindl. | Satyrium Sw. | Orchidaceae |
| Azadehdelia Braem | Cribbia Senghas | | | Azadehdelia Braem | Cribbia Senghas | Orchidaceae |
| ×Banfieldara hort. | | a | | Banfieldara hort. | | Orchidaceae |
| Baptistonia Barb. Rodr. | Gomesa R. Br. | | | Baptistonia Barb. Rodr. | Gomesa R. Br. | Orchidaceae |
| Barbosella Schltr. | | a | | Barbosella Schltr. | | Orchidaceae |
| Barbrodria Luer | | a | | Barbrodria Luer | | Orchidaceae |
| Barkeria Knowles & Westc. | | a | | Barkeria Knowles & Westc. | | Orchidaceae |
| Barlaea Rchb. f. | Cynorkis Thouars | | | Barlaea Rchb. f. | Cynorkis Thouars | Orchidaceae |
| Barlia Parl. | Himantoglossum Spreng. | | | Barlia Parl. | Himantoglossum Spreng. | Orchidaceae |
| Barombia Schltr. | Aerangis Rchb. f. | | | Barombia Schltr. | Aerangis Rchb. f. | Orchidaceae |
| Barombiella Szlach. | Rangaeris (Schltr.) Summerh. | | | Barombiella Szlach. | Rangaeris (Schltr.) Summerh. | Orchidaceae |
| Bartholina R. Br. | | a | | Bartholina R. Br. | | Orchidaceae |
| Basigyne J. J. Sm. | | a | | Basigyne J. J. Sm. | | Orchidaceae |
| Basiphyllaea Schltr. | | a | | Basiphyllaea Schltr. | | Orchidaceae |
| Baskervilla Lindl. | | a | | Baskervilla Lindl. | | Orchidaceae |
| Batemannia Lindl. | | a | | Batemannia Lindl. | | Orchidaceae |
| Bathiea Schltr. | Neobathiea Schltr. | | | Bathiea Schltr. | Neobathiea Schltr. | Orchidaceae |
| Bathiorchis Bosser & P. J. Cribb | Cheirostylis Blume | | | Bathiorchis Bosser & P. J. Cribb | Cheirostylis Blume | Orchidaceae |
| Beadlea Small | Cyclopogon C. Presl | | | Beadlea Small | Cyclopogon C. Presl | Orchidaceae |
| ×Beallara hort. | | a | | Beallara hort. | | Orchidaceae |
| Beclardia A. Rich. | | a | | Beclardia A. Rich. | | Orchidaceae |
| Beloglottis Schltr. | | a | | Beloglottis Schltr. | | Orchidaceae |
| Benthamia A. Rich. | | a | | Benthamia A. Rich. | | Orchidaceae |
| Benzingia Dodson | | a | | Benzingia Dodson | | Orchidaceae |
| Bhutanthera Renz | | a | | Bhutanthera Renz | | Orchidaceae |
| Bicchia Parl. | Habenaria Willd. | | | Bicchia Parl. | Habenaria Willd. | Orchidaceae |
| Bicornella Lindl. | Cynorkis Thouars | | | Bicornella Lindl. | Cynorkis Thouars | Orchidaceae |
| Bieneria Rchb. f. | Chloraea Lindl. | | | Bieneria Rchb. f. | Chloraea Lindl. | Orchidaceae |
| Biermannia King & Pantl. | | a | | Biermannia King & Pantl. | | Orchidaceae |
| Bifolium Nieuwl. | Neottia Guett. | | | Bifolium Nieuwl. | Neottia Guett. | Orchidaceae |
| Bifrenaria Lindl. | | a | | Bifrenaria Lindl. | | Orchidaceae |
| Bilabrella Lindl. | Habenaria Willd. | | | Bilabrella Lindl. | Habenaria Willd. | Orchidaceae |
| Binotia Rolfe | Gomesa R. Br. | | | Binotia Rolfe | Gomesa R. Br. | Orchidaceae |
| Bipinnula Comm. ex Juss. | | a | | Bipinnula Comm. ex Juss. | | Orchidaceae |
| Birchea A. Rich. | Luisia Gaudich. | | | Birchea A. Rich. | Luisia Gaudich. | Orchidaceae |
| Blephariglottis Raf. | Platanthera Rich. | | | Blephariglottis Raf. | Platanthera Rich. | Orchidaceae |
| Blepharochilum M. A. Clem. & D. L. Jones | Bulbophyllum Thouars | | | Blepharochilum M. A. Clem. & D. L. Jones | Bulbophyllum Thouars | Orchidaceae |
| Blepharoglossum (Schltr.) L. Li | Liparis Rich. | | | Blepharoglossum (Schltr.) L. Li | Liparis Rich. | Orchidaceae |
| Bletia Ruiz & Pav. | | a | | Bletia Ruiz & Pav. | | Orchidaceae |
| Bletiana Raf. | Bletia Ruiz & Pav. | | | Bletiana Raf. | Bletia Ruiz & Pav. | Orchidaceae |
| Bletilla Rchb. f. | | a | | Bletilla Rchb. f. | | Orchidaceae |
| Blumeorchis Szlach. | Cleisostoma Blume | | | Blumeorchis Szlach. | Cleisostoma Blume | Orchidaceae |
| Bogoria J. J. Sm. | | a | | Bogoria J. J. Sm. | | Orchidaceae |
| Bolbidium (Lindl.) Brieger | Dendrobium Sw. | | | Bolbidium (Lindl.) Brieger | Dendrobium Sw. | Orchidaceae |
| Bolbophyllaria Rchb. f. | Bulbophyllum Thouars | | | Bolbophyllaria Rchb. f. | Bulbophyllum Thouars | Orchidaceae |
| Bolbophyllopsis Rchb. f. | Bulbophyllum Thouars | | | Bolbophyllopsis Rchb. f. | Bulbophyllum Thouars | Orchidaceae |
| Bolborchis Lindl. | Coelogyne Lindl. | | | Bolborchis Lindl. | Coelogyne Lindl. | Orchidaceae |
| Bollea Rchb. f. | Pescatoria Rchb. f. | | | Bollea Rchb. f. | Pescatoria Rchb. f. | Orchidaceae |
| Bolusiella Schltr. | | a | | Bolusiella Schltr. | | Orchidaceae |
| Bonatea Willd. | | a | | Bonatea Willd. | | Orchidaceae |
| Bonniera Cordem. | Angraecum Bory | | | Bonniera Cordem. | Angraecum Bory | Orchidaceae |
| Bothriochilus Lem. | Coelia Lindl. | | | Bothriochilus Lem. | Coelia Lindl. | Orchidaceae |
| Bouletia M. A. Clem. & D. L. Jones | Dendrobium Sw. | | | Bouletia M. A. Clem. & D. L. Jones | Dendrobium Sw. | Orchidaceae |
| Braasiella Braem et al. | Tolumnia Raf. | | | Braasiella Braem et al. | Tolumnia Raf. | Orchidaceae |
| Brachionidium Lindl. | | a | | Brachionidium Lindl. | | Orchidaceae |
| Brachtia Rchb. f. | Brassia R. Br. | | | Brachtia Rchb. f. | Brassia R. Br. | Orchidaceae |
| Brachycorythis Lindl. | | a | | Brachycorythis Lindl. | | Orchidaceae |
| Brachypeza Garay | | a | | Brachypeza Garay | | Orchidaceae |
| Brachystele Schltr. | | a | | Brachystele Schltr. | | Orchidaceae |
| Bracisepalum J. J. Sm. | | a | | Bracisepalum J. J. Sm. | | Orchidaceae |
| Braemia Jenny | | a | | Braemia Jenny | | Orchidaceae |
| Brasilidium Campacci | Gomesa R. Br. | | | Brasilidium Campacci | Gomesa R. Br. | Orchidaceae |
| Brasiliorchis R. B. Singer et al. | | a | | Brasiliorchis R. B. Singer et al. | | Orchidaceae |
| Brasilocycnis G. Gerlach & Whitten | Lueckelia Jenny | | | Brasilocycnis G. Gerlach & Whitten | Lueckelia Jenny | Orchidaceae |
| Brassavola R. Br. | | a | | Brassavola R. Br. | | Orchidaceae |
| Brassia R. Br. | | a | | Brassia R. Br. | | Orchidaceae |
| ×Brassidium hort. | | a | | Brassidium hort. | | Orchidaceae |
| Brassiopsis Szlach. & Górniak | Brassia R. Br. | | | Brassiopsis Szlach. & Górniak | Brassia R. Br. | Orchidaceae |
| ×Brasso-cattleya hort. | | a | | Brasso-cattleya hort. | | Orchidaceae |
| ×Brassochilus hort. | | a | | Brassochilus hort. | | Orchidaceae |
| ×Brassodiacrium hort. | | a | | Brassodiacrium hort. | | Orchidaceae |
| ×Brassoepidendrum hort. | | a | | Brassoepidendrum hort. | | Orchidaceae |
| ×Brassoepilaelia hort. | | a | | Brassoepilaelia hort. | | Orchidaceae |
| ×Brassokeria hort. | | a | | Brassokeria hort. | | Orchidaceae |
| ×Brassolaelia hort. | | a | | Brassolaelia hort. | | Orchidaceae |
| ×Brassolaeliocattleya hort. | | a | | Brassolaeliocattleya hort. | | Orchidaceae |
| ×Brassotonia hort. | | a | | Brassotonia hort. | | Orchidaceae |
| ×Bratonia Moir | | a | | Bratonia Moir | | Orchidaceae |
| Brenesia Schltr. | Pleurothallis R. Br. | | | Brenesia Schltr. | Pleurothallis R. Br. | Orchidaceae |
| Briegeria Senghas | Jacquiniella Schltr. | | | Briegeria Senghas | Jacquiniella Schltr. | Orchidaceae |
| Bromheadia Lindl. | | a | | Bromheadia Lindl. | | Orchidaceae |
| Broughtonia R. Br. | | a | | Broughtonia R. Br. | | Orchidaceae |
| Brownleea Harv. ex Lindl. | | a | | Brownleea Harv. ex Lindl. | | Orchidaceae |
| Bryobium Lindl. | Eria Lindl. | | | Bryobium Lindl. | Eria Lindl. | Orchidaceae |
| Bucculina Lindl. | Holothrix Rich. ex Lindl. | | | Bucculina Lindl. | Holothrix Rich. ex Lindl. | Orchidaceae |
| Buchtienia Schltr. | | a | | Buchtienia Schltr. | | Orchidaceae |
| Bulbophyllum Thouars | | a | | Bulbophyllum Thouars | | Orchidaceae |
| Bulleyia Schltr. | | a | | Bulleyia Schltr. | | Orchidaceae |
| Bunochilus D. L. Jones & M. A. Clem. | | a | | Bunochilus D. L. Jones & M. A. Clem. | | Orchidaceae |
| Burlingtonia Lindl. | Rodriguezia Ruiz & Pav. | | | Burlingtonia Lindl. | Rodriguezia Ruiz & Pav. | Orchidaceae |
| Burnettia Lindl. | | a | | Burnettia Lindl. | | Orchidaceae |
| Burnsbaloghia Szlach. | Deiregyne Schltr. | | | Burnsbaloghia Szlach. | Deiregyne Schltr. | Orchidaceae |
| ×Burrageara hort. | | a | | Burrageara hort. | | Orchidaceae |
| Cadetia Gaudich. | Dendrobium Sw. | | | Cadetia Gaudich. | Dendrobium Sw. | Orchidaceae |
| Caladenia R. Br. | | a | | Caladenia R. Br. | | Orchidaceae |
| Caladeniastrum (Szlach.) Szlach. | | a | | Caladeniastrum (Szlach.) Szlach. | | Orchidaceae |
| Calanthe R. Br. | | a | | Calanthe R. Br. | | Orchidaceae |
| Calanthidium Pfitzer | Calanthe R. Br. | | | Calanthidium Pfitzer | Calanthe R. Br. | Orchidaceae |
| Calcearia Blume | Corybas Salisb. | | | Calcearia Blume | Corybas Salisb. | Orchidaceae |
| Calceolaria Heist. ex Fabr. | Cypripedium L. | | | Calceolaria Heist. ex Fabr. | Cypripedium L. | Orchidaceae |
| Calceolus Nieuwl. | Cypripedium L. | | | Calceolus Nieuwl. | Cypripedium L. | Orchidaceae |
| Caleana R. Br. | | a | | Caleana R. Br. | | Orchidaceae |
| Caleya R. Br. | Caleana R. Br. | | | Caleya R. Br. | Caleana R. Br. | Orchidaceae |
| Calliphyllon Bubani | Epipactis Zinn | | | Calliphyllon Bubani | Epipactis Zinn | Orchidaceae |
| Callista Lour. | Dendrobium Sw. | | | Callista Lour. | Dendrobium Sw. | Orchidaceae |
| Callithronum Ehrh. | Cephalanthera Rich. | | | Callithronum Ehrh. | Cephalanthera Rich. | Orchidaceae |
| Callostylis Blume | Eria Lindl. | | | Callostylis Blume | Eria Lindl. | Orchidaceae |
| Calochilus R. Br. | | a | | Calochilus R. Br. | | Orchidaceae |
| Caloglossum Schltr. | Cymbidiella Rolfe | | | Caloglossum Schltr. | Cymbidiella Rolfe | Orchidaceae |
| Calonemorchis Szlach. | | a | | Calonemorchis Szlach. | | Orchidaceae |
| Calopogon R. Br. | | a | | Calopogon R. Br. | | Orchidaceae |
| Calorchis Barb. Rodr. | Ponthieva R. Br. | | | Calorchis Barb. Rodr. | Ponthieva R. Br. | Orchidaceae |
| Caluera Dodson & Determann | | a | | Caluera Dodson & Determann | | Orchidaceae |
| Calymmanthera Schltr. | | a | | Calymmanthera Schltr. | | Orchidaceae |
| Calypso Salisb. | | a | | Calypso Salisb. | | Orchidaceae |
| Calypsodium Link | Calypso Salisb. | | | Calypsodium Link | Calypso Salisb. | Orchidaceae |
| Calyptrochilum Kraenzl. | | a | | Calyptrochilum Kraenzl. | | Orchidaceae |
| Camaridium Lindl. | | a | | Camaridium Lindl. | | Orchidaceae |
| Camarotis Lindl. | Micropera Lindl. | | | Camarotis Lindl. | Micropera Lindl. | Orchidaceae |
| Camelostalix Pfitzer | Pholidota Lindl. ex Hook. | | | Camelostalix Pfitzer | Pholidota Lindl. ex Hook. | Orchidaceae |
| Camilleugenia Frapp. ex Cordem. | Cynorkis Thouars | | | Camilleugenia Frapp. ex Cordem. | Cynorkis Thouars | Orchidaceae |
| Campaccia Baptista et al. | Oncidium Sw. | | | Campaccia Baptista et al. | Oncidium Sw. | Orchidaceae |
| Campanulorchis Brieger | Eria Lindl. | | | Campanulorchis Brieger | Eria Lindl. | Orchidaceae |
| Campylocentrum Benth. | | a | | Campylocentrum Benth. | | Orchidaceae |
| Canacorchis Guillaumin | Bulbophyllum Thouars | | | Canacorchis Guillaumin | Bulbophyllum Thouars | Orchidaceae |
| Cannaeorchis M. A. Clem. & D. L. Jones | Dendrobium Sw. | | | Cannaeorchis M. A. Clem. & D. L. Jones | Dendrobium Sw. | Orchidaceae |
| Capanemia Barb. Rodr. | | a | | Capanemia Barb. Rodr. | | Orchidaceae |
| Cardiochilos P. J. Cribb | | a | | Cardiochilos P. J. Cribb | | Orchidaceae |
| Cardiophyllum Ehrh. | Neottia Guett. | | | Cardiophyllum Ehrh. | Neottia Guett. | Orchidaceae |
| Carenidium Baptista | Gomesa R. Br. | | | Carenidium Baptista | Gomesa R. Br. | Orchidaceae |
| Carparomorchis M. A. Clem. & D. L. Jones | Bulbophyllum Thouars | | | Carparomorchis M. A. Clem. & D. L. Jones | Bulbophyllum Thouars | Orchidaceae |
| Carria V. P. Castro & K. G. Lacerda | Gomesa R. Br. | | | Carria V. P. Castro & K. G. Lacerda | Gomesa R. Br. | Orchidaceae |
| Carriella V. P. Castro & K. G. Lacerda | Gomesa R. Br. | | | Carriella V. P. Castro & K. G. Lacerda | Gomesa R. Br. | Orchidaceae |
| Carteretia A. Rich. | Cleisostoma Blume | | | Carteretia A. Rich. | Cleisostoma Blume | Orchidaceae |
| Castroa Guiard | Gomesa R. Br. | | | Castroa Guiard | Gomesa R. Br. | Orchidaceae |
| Catachaetum Hoffmanns. | Catasetum Rich. ex Kunth | | | Catachaetum Hoffmanns. | Catasetum Rich. ex Kunth | Orchidaceae |
| Catasetum Rich. ex Kunth | | a | | Catasetum Rich. ex Kunth | | Orchidaceae |
| Cathea Salisb. | Calopogon R. Br. | | | Cathea Salisb. | Calopogon R. Br. | Orchidaceae |
| Cattleya Lindl. | | a | | Cattleya Lindl. | | Orchidaceae |
| Cattleyella C. van den Berg & M. W. Chase | Cattleya Lindl. | | | Cattleyella C. van den Berg & M. W. Chase | Cattleya Lindl. | Orchidaceae |
| Cattleyopsis Lem. | Broughtonia R. Br. | | | Cattleyopsis Lem. | Broughtonia R. Br. | Orchidaceae |
| Caucaea Schltr. | | a | | Caucaea Schltr. | | Orchidaceae |
| Caularthron Raf. | | a | | Caularthron Raf. | | Orchidaceae |
| Celatorchis (R. Rice) R. Rice | Solenangis Schltr. | | | Celatorchis (R. Rice) R. Rice | Solenangis Schltr. | Orchidaceae |
| Centranthera Scheidw. | Pleurothallis R. Br. | | | Centranthera Scheidw. | Pleurothallis R. Br. | Orchidaceae |
| Centrochilus Schauer | Habenaria Willd. | | | Centrochilus Schauer | Habenaria Willd. | Orchidaceae |
| Centrogenium Schltr. | Eltroplectris Raf. | | | Centrogenium Schltr. | Eltroplectris Raf. | Orchidaceae |
| Centroglossa Barb. Rodr. | | a | | Centroglossa Barb. Rodr. | | Orchidaceae |
| Centropetalum Lindl. | Fernandezia Ruiz & Pav. | | | Centropetalum Lindl. | Fernandezia Ruiz & Pav. | Orchidaceae |
| Centrosia A. Rich. | Calanthe R. Br. | | | Centrosia A. Rich. | Calanthe R. Br. | Orchidaceae |
| Centrosis Thouars | Calanthe R. Br. | | | Centrosis Thouars | Calanthe R. Br. | Orchidaceae |
| Centrostigma Schltr. | | a | | Centrostigma Schltr. | | Orchidaceae |
| Cephalangraecum Schltr. | Ancistrorhynchus Finet | | | Cephalangraecum Schltr. | Ancistrorhynchus Finet | Orchidaceae |
| Cephalanthera Rich. | | a | | Cephalanthera Rich. | | Orchidaceae |
| Cephalantheropsis Guillaumin | | a | | Cephalantheropsis Guillaumin | | Orchidaceae |
| Cepobaculum M. A. Clem. & D. L. Jones | Dendrobium Sw. | | | Cepobaculum M. A. Clem. & D. L. Jones | Dendrobium Sw. | Orchidaceae |
| Ceraia Lour. | Dendrobium Sw. | | | Ceraia Lour. | Dendrobium Sw. | Orchidaceae |
| Ceratandra Eckl. ex F. A. Bauer | | a | | Ceratandra Eckl. ex F. A. Bauer | | Orchidaceae |
| Ceratium Blume | Eria Lindl. | | | Ceratium Blume | Eria Lindl. | Orchidaceae |
| Ceratobium (Lindl.) M. A. Clem. & D. L. Jones | Dendrobium Sw. | | | Ceratobium (Lindl.) M. A. Clem. & D. L. Jones | Dendrobium Sw. | Orchidaceae |
| Ceratocentron Senghas | | a | | Ceratocentron Senghas | | Orchidaceae |
| Ceratochilus Blume | Trichoglottis Blume | | | Ceratochilus Blume | Trichoglottis Blume | Orchidaceae |
| Ceratopetalorchis Szlach. et al. | | a | | Ceratopetalorchis Szlach. et al. | | Orchidaceae |
| Ceratopsis Lindl. | Epipogium J. G. Gmel. ex Borkh. | | | Ceratopsis Lindl. | Epipogium J. G. Gmel. ex Borkh. | Orchidaceae |
| Ceratostylis Blume | | a | | Ceratostylis Blume | | Orchidaceae |
| Cerochilus Lindl. | Hetaeria Blume | | | Cerochilus Lindl. | Hetaeria Blume | Orchidaceae |
| Cestichis Thouars | Liparis Rich. | | | Cestichis Thouars | Liparis Rich. | Orchidaceae |
| Chaenanthe Lindl. | Comparettia Poepp. & Endl. | | | Chaenanthe Lindl. | Comparettia Poepp. & Endl. | Orchidaceae |
| Chaetocephala Barb. Rodr. | Myoxanthus Poepp. & Endl. | | | Chaetocephala Barb. Rodr. | Myoxanthus Poepp. & Endl. | Orchidaceae |
| Chamaeangis Schltr. | Diaphananthe Schltr. | | | Chamaeangis Schltr. | Diaphananthe Schltr. | Orchidaceae |
| Chamaeanthus Schltr. ex J. J. Sm. | | a | | Chamaeanthus Schltr. ex J. J. Sm. | | Orchidaceae |
| Chamaegastrodia Makino & F. Maek. | | a | | Chamaegastrodia Makino & F. Maek. | | Orchidaceae |
| Chamaeleorchis Senghas & Lückel | Oncidium Sw. | | | Chamaeleorchis Senghas & Lückel | Oncidium Sw. | Orchidaceae |
| Chamaerepes Spreng. | Herminium L. | | | Chamaerepes Spreng. | Herminium L. | Orchidaceae |
| Chamelophyton Garay | | a | | Chamelophyton Garay | | Orchidaceae |
| Chamorchis Rich. | | a | | Chamorchis Rich. | | Orchidaceae |
| Changnienia S. S. Chien | | a | | Changnienia S. S. Chien | | Orchidaceae |
| Chaseella Summerh. | Bulbophyllum Thouars | | | Chaseella Summerh. | Bulbophyllum Thouars | Orchidaceae |
| Chaubardia Rchb. f. | | a | | Chaubardia Rchb. f. | | Orchidaceae |
| Chaubardiella Garay | | a | | Chaubardiella Garay | | Orchidaceae |
| Chauliodon Summerh. | | a | | Chauliodon Summerh. | | Orchidaceae |
| Cheiradenia Lindl. | | a | | Cheiradenia Lindl. | | Orchidaceae |
| Cheiropterocephalus Barb. Rodr. | Malaxis Sol. ex Sw. | | | Cheiropterocephalus Barb. Rodr. | Malaxis Sol. ex Sw. | Orchidaceae |
| Cheirorchis Carr | Thrixspermum Lour. | | | Cheirorchis Carr | Thrixspermum Lour. | Orchidaceae |
| Cheirostylis Blume | | a | | Cheirostylis Blume | | Orchidaceae |
| Chelonanthera Blume | Pholidota Lindl. ex Hook. | | | Chelonanthera Blume | Pholidota Lindl. ex Hook. | Orchidaceae |
| Chelonistele Pfitzer | | a | | Chelonistele Pfitzer | | Orchidaceae |
| Chelyorchis Dressler & N. H. Williams | Rossioglossum (Schltr.) Garay & G. C. Kenn. | | | Chelyorchis Dressler & N. H. Williams | Rossioglossum (Schltr.) Garay & G. C. Kenn. | Orchidaceae |
| Chelystachya Mytnik & Szlach. | Polystachya Hook. | | | Chelystachya Mytnik & Szlach. | Polystachya Hook. | Orchidaceae |
| Chenorchis Z. J. Liu et al. | Holcoglossum Schltr. | | | Chenorchis Z. J. Liu et al. | Holcoglossum Schltr. | Orchidaceae |
| Chiloglottis R. Br. | | a | | Chiloglottis R. Br. | | Orchidaceae |
| Chilopogon Schltr. | | a | | Chilopogon Schltr. | | Orchidaceae |
| Chiloschista Lindl. | | a | | Chiloschista Lindl. | | Orchidaceae |
| Chitonanthera Schltr. | Octarrhena Thwaites | | | Chitonanthera Schltr. | Octarrhena Thwaites | Orchidaceae |
| Chitonochilus Schltr. | Agrostophyllum Blume | | | Chitonochilus Schltr. | Agrostophyllum Blume | Orchidaceae |
| Chloraea Lindl. | | a | | Chloraea Lindl. | | Orchidaceae |
| Chlorosa Blume | Cryptostylis R. Br. | | | Chlorosa Blume | Cryptostylis R. Br. | Orchidaceae |
| Choeradoplectron Schauer | Habenaria Willd. | | | Choeradoplectron Schauer | Habenaria Willd. | Orchidaceae |
| Chondradenia Maxim. ex F. Maek. | | a | | Chondradenia Maxim. ex F. Maek. | | Orchidaceae |
| Chondrorhyncha Lindl. | | a | | Chondrorhyncha Lindl. | | Orchidaceae |
| Chondroscaphe (Dressler) Senghas & G. Gerlach | | a | | Chondroscaphe (Dressler) Senghas & G. Gerlach | | Orchidaceae |
| Christensonella Szlach. et al. | | a | | Christensonella Szlach. et al. | | Orchidaceae |
| Christensonia Haager | Vanda Jones ex R. Br. | | | Christensonia Haager | Vanda Jones ex R. Br. | Orchidaceae |
| Chromatotriccum M. A. Clem. & D. L. Jones | Dendrobium Sw. | | | Chromatotriccum M. A. Clem. & D. L. Jones | Dendrobium Sw. | Orchidaceae |
| Chroniochilus J. J. Sm. | | a | | Chroniochilus J. J. Sm. | | Orchidaceae |
| Chrysobaphus Wall. | Anoectochilus Blume | | | Chrysobaphus Wall. | Anoectochilus Blume | Orchidaceae |
| Chrysocycnis Linden & Rchb. f. | Mormolyca Fenzl | | | Chrysocycnis Linden & Rchb. f. | Mormolyca Fenzl | Orchidaceae |
| Chrysoglossum Blume | | a | | Chrysoglossum Blume | | Orchidaceae |
| Chusua Nevski | Ponerorchis Rchb. f. | | | Chusua Nevski | Ponerorchis Rchb. f. | Orchidaceae |
| Chysis Lindl. | | a | | Chysis Lindl. | | Orchidaceae |
| Chytroglossa Rchb. f. | | a | | Chytroglossa Rchb. f. | | Orchidaceae |
| Cionisaccus Breda | Goodyera R. Br. | | | Cionisaccus Breda | Goodyera R. Br. | Orchidaceae |
| Ciripedium Zumagl. | Cypripedium L. | | | Ciripedium Zumagl. | Cypripedium L. | Orchidaceae |
| Cirrhaea Lindl. | | a | | Cirrhaea Lindl. | | Orchidaceae |
| Cirrhopetalum Lindl. | Bulbophyllum Thouars | | | Cirrhopetalum Lindl. | Bulbophyllum Thouars | Orchidaceae |
| Cischweinfia Dressler & N. H. Williams | | a | | Cischweinfia Dressler & N. H. Williams | | Orchidaceae |
| Cistella Blume | Geodorum Jacks. | | | Cistella Blume | Geodorum Jacks. | Orchidaceae |
| Claderia Hook. f. | | a | | Claderia Hook. f. | | Orchidaceae |
| Cladobium Lindl. | Scaphyglottis Poepp. & Endl. | | | Cladobium Lindl. | Scaphyglottis Poepp. & Endl. | Orchidaceae |
| Cladobium Schltr. | Stenorrhynchos Rich. ex Spreng. | | | Cladobium Schltr. | Stenorrhynchos Rich. ex Spreng. | Orchidaceae |
| Cladorhiza Raf. | Corallorhiza Gagnebin | | | Cladorhiza Raf. | Corallorhiza Gagnebin | Orchidaceae |
| Cleisocentron Brühl | | a | | Cleisocentron Brühl | | Orchidaceae |
| Cleisomeria Lindl. ex G. Don | | a | | Cleisomeria Lindl. ex G. Don | | Orchidaceae |
| Cleisostoma Blume | | a | | Cleisostoma Blume | | Orchidaceae |
| Cleisostomopsis Seidenf. | | a | | Cleisostomopsis Seidenf. | | Orchidaceae |
| Cleistes Rich. ex Lindl. | | a | | Cleistes Rich. ex Lindl. | | Orchidaceae |
| Clematepistephium N. Hallé | | a | | Clematepistephium N. Hallé | | Orchidaceae |
| Clowesia Lindl. | | a | | Clowesia Lindl. | | Orchidaceae |
| Cnemidia Lindl. | Tropidia Lindl. | | | Cnemidia Lindl. | Tropidia Lindl. | Orchidaceae |
| Coccineorchis Schltr. | | a | | Coccineorchis Schltr. | | Orchidaceae |
| Cochleanthes Raf. | | a | | Cochleanthes Raf. | | Orchidaceae |
| Cochlia Blume | Bulbophyllum Thouars | | | Cochlia Blume | Bulbophyllum Thouars | Orchidaceae |
| Cochlioda Lindl. | Oncidium Sw. | | | Cochlioda Lindl. | Oncidium Sw. | Orchidaceae |
| Cocleorchis Szlach. | Cyclopogon C. Presl | | | Cocleorchis Szlach. | Cyclopogon C. Presl | Orchidaceae |
| Codonorchis Lindl. | | a | | Codonorchis Lindl. | | Orchidaceae |
| Codonosiphon Schltr. | Bulbophyllum Thouars | | | Codonosiphon Schltr. | Bulbophyllum Thouars | Orchidaceae |
| Coelandria Fitzg. | Dendrobium Sw. | | | Coelandria Fitzg. | Dendrobium Sw. | Orchidaceae |
| Coelia Lindl. | | a | | Coelia Lindl. | | Orchidaceae |
| Coeliopsis Rchb. f. | | a | | Coeliopsis Rchb. f. | | Orchidaceae |
| Coeloglossum Hartm. | Dactylorhiza Neck. ex Nevski | | | Coeloglossum Hartm. | Dactylorhiza Neck. ex Nevski | Orchidaceae |
| Coelogyne Lindl. | | a | | Coelogyne Lindl. | | Orchidaceae |
| Coenadenium (Summerh.) Szlach. | Angraecopsis Kraenzl. | | | Coenadenium (Summerh.) Szlach. | Angraecopsis Kraenzl. | Orchidaceae |
| Cogniauxiocharis (Schltr.) Hoehne | Stenorrhynchos Rich. ex Spreng. | | | Cogniauxiocharis (Schltr.) Hoehne | Stenorrhynchos Rich. ex Spreng. | Orchidaceae |
| Cohnia Rchb. f. | Trichocentrum Poepp. & Endl. | | | Cohnia Rchb. f. | Trichocentrum Poepp. & Endl. | Orchidaceae |
| Cohniella Pfitzer | Trichocentrum Poepp. & Endl. | | | Cohniella Pfitzer | Trichocentrum Poepp. & Endl. | Orchidaceae |
| Coilochilus Schltr. | | a | | Coilochilus Schltr. | | Orchidaceae |
| Coilostylis Raf. | Epidendrum L. | | | Coilostylis Raf. | Epidendrum L. | Orchidaceae |
| Colax Lindl. | Pabstia Garay | | | Colax Lindl. | Pabstia Garay | Orchidaceae |
| Collabiopsis S. S. Ying | Collabium Blume | | | Collabiopsis S. S. Ying | Collabium Blume | Orchidaceae |
| Collabium Blume | | a | | Collabium Blume | | Orchidaceae |
| Collare-stuartense Senghas & Bockemühl | Oncidium Sw. | | | Collare-stuartense Senghas & Bockemühl | Oncidium Sw. | Orchidaceae |
| Collea Lindl. | Pelexia Poit. ex Lindl. | | | Collea Lindl. | Pelexia Poit. ex Lindl. | Orchidaceae |
| ×Colmanara hort. | ×Miltonidium hort. | | | Colmanara hort. | Miltonidium hort. | Orchidaceae |
| Colombiana Ospina | Pleurothallis R. Br. | | | Colombiana Ospina | Pleurothallis R. Br. | Orchidaceae |
| Comparettia Poepp. & Endl. | | a | | Comparettia Poepp. & Endl. | | Orchidaceae |
| Comperia K. Koch | Himantoglossum Spreng. | | | Comperia K. Koch | Himantoglossum Spreng. | Orchidaceae |
| Conchidium Griff. | | a | | Conchidium Griff. | | Orchidaceae |
| Conchochilus Hassk. | Appendicula Blume | | | Conchochilus Hassk. | Appendicula Blume | Orchidaceae |
| Conchograecum Szlach. et al. | | a | | Conchograecum Szlach. et al. | | Orchidaceae |
| Concocidium Romowicz & Szlach. | Gomesa R. Br. | | | Concocidium Romowicz & Szlach. | Gomesa R. Br. | Orchidaceae |
| Condylago Luer | | a | | Condylago Luer | | Orchidaceae |
| Conostalix (Kraenzl.) Brieger | Dendrobium Sw. | | | Conostalix (Kraenzl.) Brieger | Dendrobium Sw. | Orchidaceae |
| Constantia Barb. Rodr. | | a | | Constantia Barb. Rodr. | | Orchidaceae |
| Cooktownia D. L. Jones | | a | | Cooktownia D. L. Jones | | Orchidaceae |
| Corallorhiza Gagnebin | | a | | Corallorhiza Gagnebin | | Orchidaceae |
| Corallorrhiza Gagnebin, orth. var. | Corallorhiza Gagnebin | | | Corallorrhiza Gagnebin, orth. var. | Corallorhiza Gagnebin | Orchidaceae |
| Cordanthera L. O. Williams | Telipogon Mutis ex Kunth | | | Cordanthera L. O. Williams | Telipogon Mutis ex Kunth | Orchidaceae |
| Cordiglottis J. J. Sm. | Thrixspermum Lour. | | | Cordiglottis J. J. Sm. | Thrixspermum Lour. | Orchidaceae |
| Cordula Raf. | Paphiopedilum Pfitzer | | | Cordula Raf. | Paphiopedilum Pfitzer | Orchidaceae |
| Cordyla Blume | Nervilia Comm. ex Gaudich. | | | Cordyla Blume | Nervilia Comm. ex Gaudich. | Orchidaceae |
| Cordylestylis Falc. | Goodyera R. Br. | | | Cordylestylis Falc. | Goodyera R. Br. | Orchidaceae |
| Corunastylis Fitzg. | Genoplesium R. Br. | | | Corunastylis Fitzg. | Genoplesium R. Br. | Orchidaceae |
| Coryanthes Hook. | | a | | Coryanthes Hook. | | Orchidaceae |
| Corybas Salisb. | | a | | Corybas Salisb. | | Orchidaceae |
| Corycium Sw. | | a | | Corycium Sw. | | Orchidaceae |
| Corymbis Thouars | Corymborkis Thouars | | | Corymbis Thouars | Corymborkis Thouars | Orchidaceae |
| Corymborchis Thouars | Corymborkis Thouars | | | Corymborchis Thouars | Corymborkis Thouars | Orchidaceae |
| Corymborkis Thouars | | a | | Corymborkis Thouars | | Orchidaceae |
| Corysanthes R. Br. | Corybas Salisb. | | | Corysanthes R. Br. | Corybas Salisb. | Orchidaceae |
| Costaricaea Schltr. | Scaphyglottis Poepp. & Endl. | | | Costaricaea Schltr. | Scaphyglottis Poepp. & Endl. | Orchidaceae |
| Cottonia Wight | | a | | Cottonia Wight | | Orchidaceae |
| Cotylolabium Garay | | a | | Cotylolabium Garay | | Orchidaceae |
| Crangonorchis D. L. Jones & M. A. Clem. | | a | | Crangonorchis D. L. Jones & M. A. Clem. | | Orchidaceae |
| Cranichis Sw. | | a | | Cranichis Sw. | | Orchidaceae |
| Cremastra Lindl. | | a | | Cremastra Lindl. | | Orchidaceae |
| Crepidium Blume | | a | | Crepidium Blume | | Orchidaceae |
| Cribbia Senghas | | a | | Cribbia Senghas | | Orchidaceae |
| Crinonia Blume | Pholidota Lindl. ex Hook. | | | Crinonia Blume | Pholidota Lindl. ex Hook. | Orchidaceae |
| Criogenes Salisb. | Cypripedium L. | | | Criogenes Salisb. | Cypripedium L. | Orchidaceae |
| Crocodeilanthe Rchb. f. & Warsz. | Pleurothallis R. Br. | | | Crocodeilanthe Rchb. f. & Warsz. | Pleurothallis R. Br. | Orchidaceae |
| Crossangis Schltr. | Rhipidoglossum Schltr. | | | Crossangis Schltr. | Rhipidoglossum Schltr. | Orchidaceae |
| Crossoglossa Dodson | | a | | Crossoglossa Dodson | | Orchidaceae |
| Crybe Lindl. | Bletia Ruiz & Pav. | | | Crybe Lindl. | Bletia Ruiz & Pav. | Orchidaceae |
| Cryptanthemis Rupp | Rhizanthella R. S. Rogers | | | Cryptanthemis Rupp | Rhizanthella R. S. Rogers | Orchidaceae |
| Cryptarrhena R. Br. | | a | | Cryptarrhena R. Br. | | Orchidaceae |
| Cryptocentrum Benth. | | a | | Cryptocentrum Benth. | | Orchidaceae |
| Cryptochilus Wall. | | a | | Cryptochilus Wall. | | Orchidaceae |
| Cryptoglottis Blume | Podochilus Blume | | | Cryptoglottis Blume | Podochilus Blume | Orchidaceae |
| Cryptophoranthus Barb. Rodr. | Pleurothallis R. Br. | | | Cryptophoranthus Barb. Rodr. | Pleurothallis R. Br. | Orchidaceae |
| Cryptopus Lindl. | | a | | Cryptopus Lindl. | | Orchidaceae |
| Cryptopylos Garay | | a | | Cryptopylos Garay | | Orchidaceae |
| Cryptosanus Scheidw. | Leochilus Knowles & Westc. | | | Cryptosanus Scheidw. | Leochilus Knowles & Westc. | Orchidaceae |
| Cryptostylis R. Br. | | a | | Cryptostylis R. Br. | | Orchidaceae |
| Ctenorchis K. Schum. | Angraecum Bory | | | Ctenorchis K. Schum. | Angraecum Bory | Orchidaceae |
| Cuculina Raf. | Catasetum Rich. ex Kunth | | | Cuculina Raf. | Catasetum Rich. ex Kunth | Orchidaceae |
| Cuitlauzina La Llave & Lex. | | a | | Cuitlauzina La Llave & Lex. | | Orchidaceae |
| Cutsis Burns-Bal. et al. | Dichromanthus Garay | | | Cutsis Burns-Bal. et al. | Dichromanthus Garay | Orchidaceae |
| Cyanaeorchis Barb. Rodr. | | a | | Cyanaeorchis Barb. Rodr. | | Orchidaceae |
| Cyanicula Hopper & A. P. Br. | | a | | Cyanicula Hopper & A. P. Br. | | Orchidaceae |
| Cyanorchis Thouars | Phaius Lour. | | | Cyanorchis Thouars | Phaius Lour. | Orchidaceae |
| Cyathoglottis Poepp. & Endl. | Sobralia Ruiz & Pav. | | | Cyathoglottis Poepp. & Endl. | Sobralia Ruiz & Pav. | Orchidaceae |
| Cybebus Garay | | a | | Cybebus Garay | | Orchidaceae |
| Cybelion Spreng. | Ionopsis Kunth | | | Cybelion Spreng. | Ionopsis Kunth | Orchidaceae |
| Cyclopogon C. Presl | | a | | Cyclopogon C. Presl | | Orchidaceae |
| Cycnoches Lindl. | | a | | Cycnoches Lindl. | | Orchidaceae |
| ×Cycnodes hort. | | a | | Cycnodes hort. | | Orchidaceae |
| Cylindrolobus (Blume) Brieger | Eria Lindl. | | | Cylindrolobus (Blume) Brieger | Eria Lindl. | Orchidaceae |
| Cymbidiella Rolfe | | a | | Cymbidiella Rolfe | | Orchidaceae |
| Cymbidium Sw. | | a | | Cymbidium Sw. | | Orchidaceae |
| Cymbiglossum Halb., nom. inval. | Rhynchostele Rchb. f. | | | Cymbiglossum Halb., nom. inval. | Rhynchostele Rchb. f. | Orchidaceae |
| Cymbilabia D. K. Liu & Ming H. Li | | a | | Cymbilabia D. K. Liu & Ming H. Li | | Orchidaceae |
| Cymboglossum (J. J. Sm.) Brieger ex Rauschert | Eria Lindl. | | | Cymboglossum (J. J. Sm.) Brieger ex Rauschert | Eria Lindl. | Orchidaceae |
| Cynorchis Thouars, orth. var. | Cynorkis Thouars | | | Cynorchis Thouars, orth. var. | Cynorkis Thouars | Orchidaceae |
| Cynorkis Thouars | | a | | Cynorkis Thouars | | Orchidaceae |
| Cynosorchis Thouars, orth. var. | Cynorkis Thouars | | | Cynosorchis Thouars, orth. var. | Cynorkis Thouars | Orchidaceae |
| Cyperorchis Blume | Cymbidium Sw. | | | Cyperorchis Blume | Cymbidium Sw. | Orchidaceae |
| Cyphochilus Schltr. | | a | | Cyphochilus Schltr. | | Orchidaceae |
| Cypholoron Dodson & Dressler | | a | | Cypholoron Dodson & Dressler | | Orchidaceae |
| Cypripedium L. | | a | | Cypripedium L. | | Orchidaceae |
| Cyrtidiorchis Rauschert | | a | | Cyrtidiorchis Rauschert | | Orchidaceae |
| Cyrtidium Schltr. | Cyrtidiorchis Rauschert | | | Cyrtidium Schltr. | Cyrtidiorchis Rauschert | Orchidaceae |
| Cyrtochiloides N. H. Williams & M. W. Chase | | a | | Cyrtochiloides N. H. Williams & M. W. Chase | | Orchidaceae |
| Cyrtochilum Kunth | | a | | Cyrtochilum Kunth | | Orchidaceae |
| Cyrtoglottis Schltr. | Mormolyca Fenzl | | | Cyrtoglottis Schltr. | Mormolyca Fenzl | Orchidaceae |
| Cyrtopera Lindl. | Eulophia R. Br. | | | Cyrtopera Lindl. | Eulophia R. Br. | Orchidaceae |
| Cyrtopodium R. Br. | | a | | Cyrtopodium R. Br. | | Orchidaceae |
| Cyrtorchis Schltr. | | a | | Cyrtorchis Schltr. | | Orchidaceae |
| Cyrtosia Blume | | a | | Cyrtosia Blume | | Orchidaceae |
| Cyrtostylis R. Br. | | a | | Cyrtostylis R. Br. | | Orchidaceae |
| Cystochilum Barb. Rodr. | Cranichis Sw. | | | Cystochilum Barb. Rodr. | Cranichis Sw. | Orchidaceae |
| Cystopus Blume | Odontochilus Blume | | | Cystopus Blume | Odontochilus Blume | Orchidaceae |
| Cystorchis Blume | | a | | Cystorchis Blume | | Orchidaceae |
| Cytherea Salisb. | Calypso Salisb. | | | Cytherea Salisb. | Calypso Salisb. | Orchidaceae |
| Cytheris Lindl. | Tainia Blume | | | Cytheris Lindl. | Tainia Blume | Orchidaceae |
| Dactylorchis (Klinge) Verm. | Dactylorhiza Neck. ex Nevski | | | Dactylorchis (Klinge) Verm. | Dactylorhiza Neck. ex Nevski | Orchidaceae |
| Dactylorhiza Neck. ex Nevski | | a | | Dactylorhiza Neck. ex Nevski | | Orchidaceae |
| Dactylorhynchus Schltr. | Bulbophyllum Thouars | | | Dactylorhynchus Schltr. | Bulbophyllum Thouars | Orchidaceae |
| Dactylostalix Rchb. f. | | a | | Dactylostalix Rchb. f. | | Orchidaceae |
| Dactylostylis Scheidw. | Zygostates Lindl. | | | Dactylostylis Scheidw. | Zygostates Lindl. | Orchidaceae |
| Daiotyla Dressler | | a | | Daiotyla Dressler | | Orchidaceae |
| Dalabrifolia (Pfitzer) Szlach. & Romowicz | Angraecum Bory | | | Dalabrifolia (Pfitzer) Szlach. & Romowicz | Angraecum Bory | Orchidaceae |
| Danhatchia Garay & Christenson | | a | | Danhatchia Garay & Christenson | | Orchidaceae |
| Danxiaorchis J. W. Zhai et al. | | a | | Danxiaorchis J. W. Zhai et al. | | Orchidaceae |
| Darwiniella Braas & Lückel | Telipogon Mutis ex Kunth | | | Darwiniella Braas & Lückel | Telipogon Mutis ex Kunth | Orchidaceae |
| Darwiniera Braas & Lückel | Telipogon Mutis ex Kunth | | | Darwiniera Braas & Lückel | Telipogon Mutis ex Kunth | Orchidaceae |
| Dasyglossum Königer & Schildh. | Cyrtochilum Kunth | | | Dasyglossum Königer & Schildh. | Cyrtochilum Kunth | Orchidaceae |
| Davejonesia M. A. Clem. | Dendrobium Sw. | | | Davejonesia M. A. Clem. | Dendrobium Sw. | Orchidaceae |
| Decaisnea Brongn. | Prescottia Lindl. | | | Decaisnea Brongn. | Prescottia Lindl. | Orchidaceae |
| Decaisnea Lindl. | Tropidia Lindl. | | | Decaisnea Lindl. | Tropidia Lindl. | Orchidaceae |
| Deceptor Seidenf. | | a | | Deceptor Seidenf. | | Orchidaceae |
| Degranvillea Determann | | a | | Degranvillea Determann | | Orchidaceae |
| Deiregyne Schltr. | | a | | Deiregyne Schltr. | | Orchidaceae |
| Deiregynopsis Rauschert | Aulosepalum Garay | | | Deiregynopsis Rauschert | Aulosepalum Garay | Orchidaceae |
| Dendrobates M. A. Clem. & D. L. Jones | Dendrobium Sw. | | | Dendrobates M. A. Clem. & D. L. Jones | Dendrobium Sw. | Orchidaceae |
| Dendrobium Sw. | | a | | Dendrobium Sw. | | Orchidaceae |
| Dendrochilum Blume | | a | | Dendrochilum Blume | | Orchidaceae |
| Dendrocoryne (Lindl.) Brieger | Dendrobium Sw. | | | Dendrocoryne (Lindl.) Brieger | Dendrobium Sw. | Orchidaceae |
| Dendrolirium Blume | Eria Lindl. | | | Dendrolirium Blume | Eria Lindl. | Orchidaceae |
| Dendrophylax Rchb. f. | | a | | Dendrophylax Rchb. f. | | Orchidaceae |
| Dendrorkis Thouars | Dendrobium Sw. | | | Dendrorkis Thouars | Dendrobium Sw. | Orchidaceae |
| Denslovia Rydb. | Habenaria Willd. | | | Denslovia Rydb. | Habenaria Willd. | Orchidaceae |
| Deppia Raf. | Lycaste Lindl. | | | Deppia Raf. | Lycaste Lindl. | Orchidaceae |
| Deroemera Rchb. f. | Holothrix Rich. ex Lindl. | | | Deroemera Rchb. f. | Holothrix Rich. ex Lindl. | Orchidaceae |
| Desmotrichum (Blume) Blume | Dendrobium Sw. | | | Desmotrichum (Blume) Blume | Dendrobium Sw. | Orchidaceae |
| Devogelia Schuit. | | a | | Devogelia Schuit. | | Orchidaceae |
| Diacrium (Lindl.) Benth. | Caularthron Raf. | | | Diacrium (Lindl.) Benth. | Caularthron Raf. | Orchidaceae |
| Diadeniopsis Szlach. | Systeloglossum Schltr. | | | Diadeniopsis Szlach. | Systeloglossum Schltr. | Orchidaceae |
| Diadenium Poepp. & Endl. | Comparettia Poepp. & Endl. | | | Diadenium Poepp. & Endl. | Comparettia Poepp. & Endl. | Orchidaceae |
| Dialissa Lindl. | Stelis Sw. | | | Dialissa Lindl. | Stelis Sw. | Orchidaceae |
| Diaphananthe Schltr. | | a | | Diaphananthe Schltr. | | Orchidaceae |
| Diceratostele Summerh. | | a | | Diceratostele Summerh. | | Orchidaceae |
| Dicerostylis Blume | Hylophila Lindl. | | | Dicerostylis Blume | Hylophila Lindl. | Orchidaceae |
| Dichaea Lindl. | | a | | Dichaea Lindl. | | Orchidaceae |
| Dichaeopsis Pfitzer | Dichaea Lindl. | | | Dichaeopsis Pfitzer | Dichaea Lindl. | Orchidaceae |
| Dichopus Blume | Dendrobium Sw. | | | Dichopus Blume | Dendrobium Sw. | Orchidaceae |
| Dichromanthus Garay | | a | | Dichromanthus Garay | | Orchidaceae |
| Dickasonia L. O. Williams | | a | | Dickasonia L. O. Williams | | Orchidaceae |
| Dicranotaenia Finet | Microcoelia Lindl. | | | Dicranotaenia Finet | Microcoelia Lindl. | Orchidaceae |
| Dicrypta Lindl. | Heterotaxis Lindl. | | | Dicrypta Lindl. | Heterotaxis Lindl. | Orchidaceae |
| Dictyophyllaria Garay | | a | | Dictyophyllaria Garay | | Orchidaceae |
| Didactyle Lindl. | Bulbophyllum Thouars | | | Didactyle Lindl. | Bulbophyllum Thouars | Orchidaceae |
| Didiciea King & Prain | Tipularia Nutt. | | | Didiciea King & Prain | Tipularia Nutt. | Orchidaceae |
| Didothion Raf. | Epidendrum L. | | | Didothion Raf. | Epidendrum L. | Orchidaceae |
| Didymoplexiella Garay | | a | | Didymoplexiella Garay | | Orchidaceae |
| Didymoplexiopsis Seidenf. | | a | | Didymoplexiopsis Seidenf. | | Orchidaceae |
| Didymoplexis Griff. | | a | | Didymoplexis Griff. | | Orchidaceae |
| Dienia Lindl. | Malaxis Sol. ex Sw. | | | Dienia Lindl. | Malaxis Sol. ex Sw. | Orchidaceae |
| Diglyphis Blume, orth. var. | Diglyphosa Blume | | | Diglyphis Blume, orth. var. | Diglyphosa Blume | Orchidaceae |
| Diglyphosa Blume | | a | | Diglyphosa Blume | | Orchidaceae |
| Dignathe Lindl. | Cuitlauzina La Llave & Lex. | | | Dignathe Lindl. | Cuitlauzina La Llave & Lex. | Orchidaceae |
| Digomphotis Raf. | Habenaria Willd. | | | Digomphotis Raf. | Habenaria Willd. | Orchidaceae |
| Dikylikostigma Kraenzl. | Discyphus Schltr. | | | Dikylikostigma Kraenzl. | Discyphus Schltr. | Orchidaceae |
| Dilochia Lindl. | | a | | Dilochia Lindl. | | Orchidaceae |
| Dilochiopsis (Hook. f.) Brieger | Eria Lindl. | | | Dilochiopsis (Hook. f.) Brieger | Eria Lindl. | Orchidaceae |
| Dilomilis Raf. | | a | | Dilomilis Raf. | | Orchidaceae |
| Dimerandra Schltr. | | a | | Dimerandra Schltr. | | Orchidaceae |
| Dimorphorchis Rolfe | | a | | Dimorphorchis Rolfe | | Orchidaceae |
| Dinema Lindl. | Encyclia Hook. | | | Dinema Lindl. | Encyclia Hook. | Orchidaceae |
| Dinklageella Mansf. | | a | | Dinklageella Mansf. | | Orchidaceae |
| Diodonopsis Pridgeon & M. W. Chase | | a | | Diodonopsis Pridgeon & M. W. Chase | | Orchidaceae |
| Diothonea Lindl. | Epidendrum L. | | | Diothonea Lindl. | Epidendrum L. | Orchidaceae |
| Dipera Spreng. | Disperis Sw. | | | Dipera Spreng. | Disperis Sw. | Orchidaceae |
| Diphryllum Raf. | Neottia Guett. | | | Diphryllum Raf. | Neottia Guett. | Orchidaceae |
| Diphyes Blume | Bulbophyllum Thouars | | | Diphyes Blume | Bulbophyllum Thouars | Orchidaceae |
| Diphylax Hook. f. | | a | | Diphylax Hook. f. | | Orchidaceae |
| Diplandrorchis S. C. Chen | Neottia Guett. | | | Diplandrorchis S. C. Chen | Neottia Guett. | Orchidaceae |
| Diplanthera Raf. | Platanthera Rich. | | | Diplanthera Raf. | Platanthera Rich. | Orchidaceae |
| Diplecthrum Pers. | Satyrium Sw. | | | Diplecthrum Pers. | Satyrium Sw. | Orchidaceae |
| Diplectraden Raf. | Habenaria Willd. | | | Diplectraden Raf. | Habenaria Willd. | Orchidaceae |
| Diplocaulobium (Rchb. f.) Kraenzl. | Dendrobium Sw. | | | Diplocaulobium (Rchb. f.) Kraenzl. | Dendrobium Sw. | Orchidaceae |
| Diplocentrum Lindl. | | a | | Diplocentrum Lindl. | | Orchidaceae |
| Diplochilus Lindl. | Diplomeris D. Don | | | Diplochilus Lindl. | Diplomeris D. Don | Orchidaceae |
| Diploconchium Schauer | Agrostophyllum Blume | | | Diploconchium Schauer | Agrostophyllum Blume | Orchidaceae |
| Diplodium Sw. | Pterostylis R. Br. | | | Diplodium Sw. | Pterostylis R. Br. | Orchidaceae |
| Diplolabellum F. Maek. | Oreorchis Lindl. | | | Diplolabellum F. Maek. | Oreorchis Lindl. | Orchidaceae |
| Diplomeris D. Don | | a | | Diplomeris D. Don | | Orchidaceae |
| Diploprora Hook. f. | | a | | Diploprora Hook. f. | | Orchidaceae |
| Dipodium R. Br. | | a | | Dipodium R. Br. | | Orchidaceae |
| Dipteranthus Barb. Rodr. | Zygostates Lindl. | | | Dipteranthus Barb. Rodr. | Zygostates Lindl. | Orchidaceae |
| Dipterostele Schltr. | Telipogon Mutis ex Kunth | | | Dipterostele Schltr. | Telipogon Mutis ex Kunth | Orchidaceae |
| Disa P. J. Bergius | | a | | Disa P. J. Bergius | | Orchidaceae |
| Discyphus Schltr. | | a | | Discyphus Schltr. | | Orchidaceae |
| Diseris Wight | Disperis Sw. | | | Diseris Wight | Disperis Sw. | Orchidaceae |
| Disperanthoceros Mytnik & Szlach. | Polystachya Hook. | | | Disperanthoceros Mytnik & Szlach. | Polystachya Hook. | Orchidaceae |
| Disperis Sw. | | a | | Disperis Sw. | | Orchidaceae |
| Dissorhynchium Schauer | Habenaria Willd. | | | Dissorhynchium Schauer | Habenaria Willd. | Orchidaceae |
| Distichis Thouars | Liparis Rich. | | | Distichis Thouars | Liparis Rich. | Orchidaceae |
| Distichorchis M. A. Clem. & D. L. Jones | Dendrobium Sw. | | | Distichorchis M. A. Clem. & D. L. Jones | Dendrobium Sw. | Orchidaceae |
| Distomaea Spenn. | Neottia Guett. | | | Distomaea Spenn. | Neottia Guett. | Orchidaceae |
| Distylodon Summerh. | | a | | Distylodon Summerh. | | Orchidaceae |
| Diteilis Raf. | Liparis Rich. | | | Diteilis Raf. | Liparis Rich. | Orchidaceae |
| Dithrix (Hook. f.) Schltr. ex Brummitt | Habenaria Willd. | | | Dithrix (Hook. f.) Schltr. ex Brummitt | Habenaria Willd. | Orchidaceae |
| Dithyridanthus Garay | Deiregyne Schltr. | | | Dithyridanthus Garay | Deiregyne Schltr. | Orchidaceae |
| Ditulima Raf. | Dendrobium Sw. | | | Ditulima Raf. | Dendrobium Sw. | Orchidaceae |
| Diuris Sm. | | a | | Diuris Sm. | | Orchidaceae |
| Dockrillia Brieger | Dendrobium Sw. | | | Dockrillia Brieger | Dendrobium Sw. | Orchidaceae |
| Dodsonia Ackerman | Stenia Lindl. | | | Dodsonia Ackerman | Stenia Lindl. | Orchidaceae |
| Dolichocentrum (Schltr.) Brieger | Dendrobium Sw. | | | Dolichocentrum (Schltr.) Brieger | Dendrobium Sw. | Orchidaceae |
| Domingoa Schltr. | | a | | Domingoa Schltr. | | Orchidaceae |
| ×Doritaenopsis Guillaumin | Phalaenopsis Blume | | | Doritaenopsis Guillaumin | Phalaenopsis Blume | Orchidaceae |
| Doritis Lindl. | Phalaenopsis Blume | | | Doritis Lindl. | Phalaenopsis Blume | Orchidaceae |
| Dorycheile Rchb. | Cephalanthera Rich. | | | Dorycheile Rchb. | Cephalanthera Rich. | Orchidaceae |
| Dossinia C. Morren | | a | | Dossinia C. Morren | | Orchidaceae |
| Dothilis Raf. | Spiranthes Rich. | | | Dothilis Raf. | Spiranthes Rich. | Orchidaceae |
| Dothilophis Raf. | Epidendrum L. | | | Dothilophis Raf. | Epidendrum L. | Orchidaceae |
| Doxosma Raf. | Epidendrum L. | | | Doxosma Raf. | Epidendrum L. | Orchidaceae |
| Dracomonticola H. P. Linder & Kurzweil | | a | | Dracomonticola H. P. Linder & Kurzweil | | Orchidaceae |
| Draconanthes Luer | | a | | Draconanthes Luer | | Orchidaceae |
| Dracula Luer | | a | | Dracula Luer | | Orchidaceae |
| Drakaea Lindl. | | a | | Drakaea Lindl. | | Orchidaceae |
| Drakonorchis (Hopper & A. P. Br.) D. L. Jones & M. A. Clem. | Caladenia R. Br. | | | Drakonorchis (Hopper & A. P. Br.) D. L. Jones & M. A. Clem. | Caladenia R. Br. | Orchidaceae |
| Dresslerella Luer | | a | | Dresslerella Luer | | Orchidaceae |
| Dressleria Dodson | | a | | Dressleria Dodson | | Orchidaceae |
| Dressleriella Brieger, nom. inval. | Jacquiniella Schltr. | | | Dressleriella Brieger, nom. inval. | Jacquiniella Schltr. | Orchidaceae |
| Dryadella Luer | | a | | Dryadella Luer | | Orchidaceae |
| Dryadorchis Schltr. | | a | | Dryadorchis Schltr. | | Orchidaceae |
| Drymoanthus Nicholls | | a | | Drymoanthus Nicholls | | Orchidaceae |
| Drymoda Lindl. | Bulbophyllum Thouars | | | Drymoda Lindl. | Bulbophyllum Thouars | Orchidaceae |
| Dryopeia Thouars | Disperis Sw. | | | Dryopeia Thouars | Disperis Sw. | Orchidaceae |
| Dryorkis Thouars | Disperis Sw. | | | Dryorkis Thouars | Disperis Sw. | Orchidaceae |
| Duboisia H. Karst. | Myoxanthus Poepp. & Endl. | | | Duboisia H. Karst. | Myoxanthus Poepp. & Endl. | Orchidaceae |
| Dubois-Reymondia H. Karst. | Myoxanthus Poepp. & Endl. | | | Dubois-Reymondia H. Karst. | Myoxanthus Poepp. & Endl. | Orchidaceae |
| Duckeella Porto & Brade | | a | | Duckeella Porto & Brade | | Orchidaceae |
| Dungsia Chiron & V. P. Castro | | a | | Dungsia Chiron & V. P. Castro | | Orchidaceae |
| Dunstervillea Garay | | a | | Dunstervillea Garay | | Orchidaceae |
| Durabaculum M. A. Clem. & D. L. Jones | Dendrobium Sw. | | | Durabaculum M. A. Clem. & D. L. Jones | Dendrobium Sw. | Orchidaceae |
| Dyakia Christenson | | a | | Dyakia Christenson | | Orchidaceae |
| Earina Lindl. | | a | | Earina Lindl. | | Orchidaceae |
| Eburophyton A. Heller | Cephalanthera Rich. | | | Eburophyton A. Heller | Cephalanthera Rich. | Orchidaceae |
| Echinoglossum Blume | Cleisostoma Blume | | | Echinoglossum Blume | Cleisostoma Blume | Orchidaceae |
| Echinorhyncha Dressler | | a | | Echinorhyncha Dressler | | Orchidaceae |
| Echinosepala Pridgeon & M. W. Chase | | a | | Echinosepala Pridgeon & M. W. Chase | | Orchidaceae |
| Eckartia Rchb. f. | Peristeria Hook. | | | Eckartia Rchb. f. | Peristeria Hook. | Orchidaceae |
| Eclecticus P. O'Byrne | | a | | Eclecticus P. O'Byrne | | Orchidaceae |
| Ecuadoria Dodson | Microthelys Garay | | | Ecuadoria Dodson | Microthelys Garay | Orchidaceae |
| Eggelingia Summerh. | | a | | Eggelingia Summerh. | | Orchidaceae |
| Elasmatium Dulac | Goodyera R. Br. | | | Elasmatium Dulac | Goodyera R. Br. | Orchidaceae |
| Eleorchis F. Maek. | | a | | Eleorchis F. Maek. | | Orchidaceae |
| Eleutheroglossum (Schltr.) M. A. Clem. & D. L. Jones | Dendrobium Sw. | | | Eleutheroglossum (Schltr.) M. A. Clem. & D. L. Jones | Dendrobium Sw. | Orchidaceae |
| Elleanthus C. Presl | | a | | Elleanthus C. Presl | | Orchidaceae |
| Eloyella P. Ortíz | | a | | Eloyella P. Ortíz | | Orchidaceae |
| Eltroplectris Raf. | | a | | Eltroplectris Raf. | | Orchidaceae |
| Elythranthera (Endl.) A. S. George | | a | | Elythranthera (Endl.) A. S. George | | Orchidaceae |
| Embreea Dodson | | a | | Embreea Dodson | | Orchidaceae |
| Empusa Lindl. | Liparis Rich. | | | Empusa Lindl. | Liparis Rich. | Orchidaceae |
| Empusaria Rchb. f. | Liparis Rich. | | | Empusaria Rchb. f. | Liparis Rich. | Orchidaceae |
| Encheiridion Summerh. | Microcoelia Lindl. | | | Encheiridion Summerh. | Microcoelia Lindl. | Orchidaceae |
| Encyclia Hook. | | a | | Encyclia Hook. | | Orchidaceae |
| Endeisa Raf. | Dendrobium Sw. | | | Endeisa Raf. | Dendrobium Sw. | Orchidaceae |
| Endresiella Schltr. | Trevoria F. Lehm. | | | Endresiella Schltr. | Trevoria F. Lehm. | Orchidaceae |
| Enothrea Raf. | Octomeria R. Br. | | | Enothrea Raf. | Octomeria R. Br. | Orchidaceae |
| Entaticus Gray | Habenaria Willd. | | | Entaticus Gray | Habenaria Willd. | Orchidaceae |
| Entomophobia de Vogel | | a | | Entomophobia de Vogel | | Orchidaceae |
| Eparmatostigma Garay | Vanda Jones ex R. Br. | | | Eparmatostigma Garay | Vanda Jones ex R. Br. | Orchidaceae |
| Ephemerantha P. F. Hunt & Summerh. | Dendrobium Sw. | | | Ephemerantha P. F. Hunt & Summerh. | Dendrobium Sw. | Orchidaceae |
| Ephippianthus Rchb. f. | | a | | Ephippianthus Rchb. f. | | Orchidaceae |
| Ephippium Blume | Bulbophyllum Thouars | | | Ephippium Blume | Bulbophyllum Thouars | Orchidaceae |
| Epibator Luer | | a | | Epibator Luer | | Orchidaceae |
| Epiblastus Schltr. | | a | | Epiblastus Schltr. | | Orchidaceae |
| Epiblema R. Br. | | a | | Epiblema R. Br. | | Orchidaceae |
| Epicladium Small | Epidendrum L. | | | Epicladium Small | Epidendrum L. | Orchidaceae |
| Epicranthes Blume | Bulbophyllum Thouars | | | Epicranthes Blume | Bulbophyllum Thouars | Orchidaceae |
| Epicranthus Blume | Bulbophyllum Thouars | | | Epicranthus Blume | Bulbophyllum Thouars | Orchidaceae |
| Epicrianthes Blume, orth. var. | Bulbophyllum Thouars | | | Epicrianthes Blume, orth. var. | Bulbophyllum Thouars | Orchidaceae |
| Epidanthus L. O. Williams | Epidendrum L. | | | Epidanthus L. O. Williams | Epidendrum L. | Orchidaceae |
| Epidendropsis Garay & Dunst. | Epidendrum L. | | | Epidendropsis Garay & Dunst. | Epidendrum L. | Orchidaceae |
| Epidendrum L. | | a | | Epidendrum L. | | Orchidaceae |
| Epigeneium Gagnep. | | a | | Epigeneium Gagnep. | | Orchidaceae |
| Epilyna Schltr. | Elleanthus C. Presl | | | Epilyna Schltr. | Elleanthus C. Presl | Orchidaceae |
| Epipactis Zinn | | a | | Epipactis Zinn | | Orchidaceae |
| Epiphora Lindl. | Polystachya Hook. | | | Epiphora Lindl. | Polystachya Hook. | Orchidaceae |
| Epiphorella Mytnik & Szlach. | Polystachya Hook. | | | Epiphorella Mytnik & Szlach. | Polystachya Hook. | Orchidaceae |
| Epipogium J. G. Gmel. ex Borkh. | | a | | Epipogium J. G. Gmel. ex Borkh. | | Orchidaceae |
| Epipogon S. G. Gmel., orth. var. | Epipogium J. G. Gmel. ex Borkh. | | | Epipogon S. G. Gmel., orth. var. | Epipogium J. G. Gmel. ex Borkh. | Orchidaceae |
| Epistephium Kunth | | a | | Epistephium Kunth | | Orchidaceae |
| Erasanthe P. J. Cribb et al. | | a | | Erasanthe P. J. Cribb et al. | | Orchidaceae |
| Eremorchis D. L. Jones & M. A. Clem. | | a | | Eremorchis D. L. Jones & M. A. Clem. | | Orchidaceae |
| Eria Lindl. | | a | | Eria Lindl. | | Orchidaceae |
| Eriaxis Rchb. f. | | a | | Eriaxis Rchb. f. | | Orchidaceae |
| Ericksonella Hopper & A. P. Br. | | a | | Ericksonella Hopper & A. P. Br. | | Orchidaceae |
| Eriochilum Ritgen | Eriochilus R. Br. | | | Eriochilum Ritgen | Eriochilus R. Br. | Orchidaceae |
| Eriochilus R. Br. | | a | | Eriochilus R. Br. | | Orchidaceae |
| Eriochylus Steud. | Eriochilus R. Br. | | | Eriochylus Steud. | Eriochilus R. Br. | Orchidaceae |
| Eriodes Rolfe | | a | | Eriodes Rolfe | | Orchidaceae |
| Eriopexis (Schltr.) Brieger | Dendrobium Sw. | | | Eriopexis (Schltr.) Brieger | Dendrobium Sw. | Orchidaceae |
| Eriopsis Lindl. | | a | | Eriopsis Lindl. | | Orchidaceae |
| Erioxantha Raf. | Eria Lindl. | | | Erioxantha Raf. | Eria Lindl. | Orchidaceae |
| Erycina Lindl. | | a | | Erycina Lindl. | | Orchidaceae |
| Erythrodes Blume | | a | | Erythrodes Blume | | Orchidaceae |
| Erythrorchis Blume | | a | | Erythrorchis Blume | | Orchidaceae |
| Esmeralda Rchb. f. | Arachnis Blume | | | Esmeralda Rchb. f. | Arachnis Blume | Orchidaceae |
| Espinhassoa Salazar & J. A. N. Bat. | | a | | Espinhassoa Salazar & J. A. N. Bat. | | Orchidaceae |
| Etaeria Blume, orth. var. | Hetaeria Blume | | | Etaeria Blume, orth. var. | Hetaeria Blume | Orchidaceae |
| Euanthe Schltr. | Vanda Jones ex R. Br. | | | Euanthe Schltr. | Vanda Jones ex R. Br. | Orchidaceae |
| Euchile (Dressler & G. E. Pollard) Withner | Prosthechea Knowles & Westc. | | | Euchile (Dressler & G. E. Pollard) Withner | Prosthechea Knowles & Westc. | Orchidaceae |
| Eucnemia Rchb., orth. var. | Govenia Lindl. | | | Eucnemia Rchb., orth. var. | Govenia Lindl. | Orchidaceae |
| Eucnemis Lindl. | Govenia Lindl. | | | Eucnemis Lindl. | Govenia Lindl. | Orchidaceae |
| Eucosia Blume | Goodyera R. Br. | | | Eucosia Blume | Goodyera R. Br. | Orchidaceae |
| Eudisanthema Neck. ex Post & Kuntze | Brassavola R. Br. | | | Eudisanthema Neck. ex Post & Kuntze | Brassavola R. Br. | Orchidaceae |
| Eulophia R. Br. | | a | | Eulophia R. Br. | | Orchidaceae |
| Eulophidium Pfitzer | Oeceoclades Lindl. | | | Eulophidium Pfitzer | Oeceoclades Lindl. | Orchidaceae |
| Eulophiella Rolfe | | a | | Eulophiella Rolfe | | Orchidaceae |
| Eulophiopsis Pfitzer | Graphorkis Thouars | | | Eulophiopsis Pfitzer | Graphorkis Thouars | Orchidaceae |
| Euothonaea Rchb. f. | Scaphyglottis Poepp. & Endl. | | | Euothonaea Rchb. f. | Scaphyglottis Poepp. & Endl. | Orchidaceae |
| Euphlebium (Kraenzl.) Brieger | Dendrobium Sw. | | | Euphlebium (Kraenzl.) Brieger | Dendrobium Sw. | Orchidaceae |
| Euproboscis Griff. | Thelasis Blume | | | Euproboscis Griff. | Thelasis Blume | Orchidaceae |
| Euryblema Dressler | | a | | Euryblema Dressler | | Orchidaceae |
| Eurycaulis M. A. Clem. & D. L. Jones | Dendrobium Sw. | | | Eurycaulis M. A. Clem. & D. L. Jones | Dendrobium Sw. | Orchidaceae |
| Eurycentrum Schltr. | | a | | Eurycentrum Schltr. | | Orchidaceae |
| Eurychone Schltr. | | a | | Eurychone Schltr. | | Orchidaceae |
| Eurystyles Wawra | | a | | Eurystyles Wawra | | Orchidaceae |
| Evelyna Poepp. & Endl. | Elleanthus C. Presl | | | Evelyna Poepp. & Endl. | Elleanthus C. Presl | Orchidaceae |
| Evota (Lindl.) Rolfe | Ceratandra Eckl. ex F. A. Bauer | | | Evota (Lindl.) Rolfe | Ceratandra Eckl. ex F. A. Bauer | Orchidaceae |
| Evotella H. Kurzweil & H. P. Linder | | a | | Evotella H. Kurzweil & H. P. Linder | | Orchidaceae |
| Evrardia Gagnep. | Odontochilus Blume | | | Evrardia Gagnep. | Odontochilus Blume | Orchidaceae |
| Evrardiana Aver. | Odontochilus Blume | | | Evrardiana Aver. | Odontochilus Blume | Orchidaceae |
| Evrardianthe Rauschert | Odontochilus Blume | | | Evrardianthe Rauschert | Odontochilus Blume | Orchidaceae |
| Exalaria Garay & G. A. Romero | | a | | Exalaria Garay & G. A. Romero | | Orchidaceae |
| Exeria Raf. | Eria Lindl. | | | Exeria Raf. | Eria Lindl. | Orchidaceae |
| Exochanthus M. A. Clem. & D. L. Jones | Dendrobium Sw. | | | Exochanthus M. A. Clem. & D. L. Jones | Dendrobium Sw. | Orchidaceae |
| Exophya Raf. | Epidendrum L. | | | Exophya Raf. | Epidendrum L. | Orchidaceae |
| Fernandezia Ruiz & Pav. | | a | | Fernandezia Ruiz & Pav. | | Orchidaceae |
| Ferruminaria Garay et al. | Bulbophyllum Thouars | | | Ferruminaria Garay et al. | Bulbophyllum Thouars | Orchidaceae |
| Fieldia Gaudich. | Vandopsis Pfitzer | | | Fieldia Gaudich. | Vandopsis Pfitzer | Orchidaceae |
| Fimbriella Farw. ex Butzin | | a | | Fimbriella Farw. ex Butzin | | Orchidaceae |
| Finetia Schltr. | Neofinetia Hu | | | Finetia Schltr. | Neofinetia Hu | Orchidaceae |
| Fingardia Szlach. | Crepidium Blume | | | Fingardia Szlach. | Crepidium Blume | Orchidaceae |
| Fissipes Small | Cypripedium L. | | | Fissipes Small | Cypripedium L. | Orchidaceae |
| Flickingeria A. D. Hawkes | Dendrobium Sw. | | | Flickingeria A. D. Hawkes | Dendrobium Sw. | Orchidaceae |
| Forbesina Ridl. | | a | | Forbesina Ridl. | | Orchidaceae |
| Forficaria Lindl. | Disa P. J. Bergius | | | Forficaria Lindl. | Disa P. J. Bergius | Orchidaceae |
| Fractiunguis Schltr. | Reichenbachanthus Barb. Rodr. | | | Fractiunguis Schltr. | Reichenbachanthus Barb. Rodr. | Orchidaceae |
| Fregea Rchb. f. | Sobralia Ruiz & Pav. | | | Fregea Rchb. f. | Sobralia Ruiz & Pav. | Orchidaceae |
| Frondaria Luer | | a | | Frondaria Luer | | Orchidaceae |
| Froscula Raf. | Dendrobium Sw. | | | Froscula Raf. | Dendrobium Sw. | Orchidaceae |
| Fruticicola (Schltr.) M. A. Clem. & D. L. Jones | Bulbophyllum Thouars | | | Fruticicola (Schltr.) M. A. Clem. & D. L. Jones | Bulbophyllum Thouars | Orchidaceae |
| Fuertesiella Schltr. | | a | | Fuertesiella Schltr. | | Orchidaceae |
| Funckiella Schltr., orth. var. | Funkiella Schltr. | | | Funckiella Schltr., orth. var. | Funkiella Schltr. | Orchidaceae |
| Funkiella Schltr. | | a | | Funkiella Schltr. | | Orchidaceae |
| Gabertia Gaudich. | Grammatophyllum Blume | | | Gabertia Gaudich. | Grammatophyllum Blume | Orchidaceae |
| Galeandra Lindl. | | a | | Galeandra Lindl. | | Orchidaceae |
| Galearis Raf. | | a | | Galearis Raf. | | Orchidaceae |
| Galeoglossum A. Rich. & Galeotti | | a | | Galeoglossum A. Rich. & Galeotti | | Orchidaceae |
| Galeola Lour. | | a | | Galeola Lour. | | Orchidaceae |
| Galeorchis Rydb. | Orchis L. | | | Galeorchis Rydb. | Orchis L. | Orchidaceae |
| Galeottia A. Rich. | | a | | Galeottia A. Rich. | | Orchidaceae |
| Galeottiella Schltr. | | a | | Galeottiella Schltr. | | Orchidaceae |
| Galera Blume | Epipogium J. G. Gmel. ex Borkh. | | | Galera Blume | Epipogium J. G. Gmel. ex Borkh. | Orchidaceae |
| Gamaria Raf. | Disa P. J. Bergius | | | Gamaria Raf. | Disa P. J. Bergius | Orchidaceae |
| Gamoplexis Falc. | Gastrodia R. Br. | | | Gamoplexis Falc. | Gastrodia R. Br. | Orchidaceae |
| Gamosepalum Schltr. | Aulosepalum Garay | | | Gamosepalum Schltr. | Aulosepalum Garay | Orchidaceae |
| Garaya Szlach. | Mesadenella Pabst & Garay | | | Garaya Szlach. | Mesadenella Pabst & Garay | Orchidaceae |
| Garayanthus Szlach. | Cleisostoma Blume | | | Garayanthus Szlach. | Cleisostoma Blume | Orchidaceae |
| Garayella Brieger, nom. inval. | Chamelophyton Garay | | | Garayella Brieger, nom. inval. | Chamelophyton Garay | Orchidaceae |
| Gastorchis Thouars | Phaius Lour. | | | Gastorchis Thouars | Phaius Lour. | Orchidaceae |
| Gastrochilus D. Don | | a | | Gastrochilus D. Don | | Orchidaceae |
| Gastrodia R. Br. | | a | | Gastrodia R. Br. | | Orchidaceae |
| Gastroglottis Blume | Liparis Rich. | | | Gastroglottis Blume | Liparis Rich. | Orchidaceae |
| Gastrorchis Schltr. | Phaius Lour. | | | Gastrorchis Schltr. | Phaius Lour. | Orchidaceae |
| Gastrosiphon (Schltr.) M. A. Clem. & D. L. Jones | | a | | Gastrosiphon (Schltr.) M. A. Clem. & D. L. Jones | | Orchidaceae |
| Gavilea Poepp. | | a | | Gavilea Poepp. | | Orchidaceae |
| Geerinckia Mytnik & Szlach. | Polystachya Hook. | | | Geerinckia Mytnik & Szlach. | Polystachya Hook. | Orchidaceae |
| Geesinkorchis de Vogel | | a | | Geesinkorchis de Vogel | | Orchidaceae |
| Geissanthera Schltr. | Taeniophyllum Blume | | | Geissanthera Schltr. | Taeniophyllum Blume | Orchidaceae |
| Gennaria Parl. | | a | | Gennaria Parl. | | Orchidaceae |
| Genoplesium R. Br. | | a | | Genoplesium R. Br. | | Orchidaceae |
| Genyorchis Schltr. | Bulbophyllum Thouars | | | Genyorchis Schltr. | Bulbophyllum Thouars | Orchidaceae |
| Geobina Raf. | Goodyera R. Br. | | | Geobina Raf. | Goodyera R. Br. | Orchidaceae |
| Geoblasta Barb. Rodr. | | a | | Geoblasta Barb. Rodr. | | Orchidaceae |
| Geocalpa Brieger, nom. inval. | Pleurothallis R. Br. | | | Geocalpa Brieger, nom. inval. | Pleurothallis R. Br. | Orchidaceae |
| Geodorum Jacks. | | a | | Geodorum Jacks. | | Orchidaceae |
| Georchis Lindl. | Goodyera R. Br. | | | Georchis Lindl. | Goodyera R. Br. | Orchidaceae |
| Gerlachia Szlach. | Stanhopea J. Frost ex Hook. | | | Gerlachia Szlach. | Stanhopea J. Frost ex Hook. | Orchidaceae |
| Gersinia Néraud | Dendrobium Sw. | | | Gersinia Néraud | Dendrobium Sw. | Orchidaceae |
| Ghiesbreghtia A. Rich. & Galeotti | Calanthe R. Br. | | | Ghiesbreghtia A. Rich. & Galeotti | Calanthe R. Br. | Orchidaceae |
| Gigliolia Barb. Rodr. | Octomeria R. Br. | | | Gigliolia Barb. Rodr. | Octomeria R. Br. | Orchidaceae |
| Giulianettia Rolfe | Glomera Blume | | | Giulianettia Rolfe | Glomera Blume | Orchidaceae |
| Glomera Blume | | a | | Glomera Blume | | Orchidaceae |
| Glossaspis Spreng. | Habenaria Willd. | | | Glossaspis Spreng. | Habenaria Willd. | Orchidaceae |
| Glossochilopsis Szlach. | Crepidium Blume | | | Glossochilopsis Szlach. | Crepidium Blume | Orchidaceae |
| Glossodia R. Br. | | a | | Glossodia R. Br. | | Orchidaceae |
| Glossorhyncha Ridl. | Glomera Blume | | | Glossorhyncha Ridl. | Glomera Blume | Orchidaceae |
| Glossula Lindl. | Habenaria Willd. | | | Glossula Lindl. | Habenaria Willd. | Orchidaceae |
| Glottisarcon Szlach. & Kolan. | | a | | Glottisarcon Szlach. & Kolan. | | Orchidaceae |
| Goadbyella R. S. Rogers | Microtis R. Br. | | | Goadbyella R. S. Rogers | Microtis R. Br. | Orchidaceae |
| Goldschmidtia Dammer | Dendrobium Sw. | | | Goldschmidtia Dammer | Dendrobium Sw. | Orchidaceae |
| Gomesa R. Br. | | a | | Gomesa R. Br. | | Orchidaceae |
| Gomphichis Lindl. | | a | | Gomphichis Lindl. | | Orchidaceae |
| Gonatostylis Schltr. | | a | | Gonatostylis Schltr. | | Orchidaceae |
| Gongora Ruiz & Pav. | | a | | Gongora Ruiz & Pav. | | Orchidaceae |
| Goniochilus M. W. Chase | Leochilus Knowles & Westc. | | | Goniochilus M. W. Chase | Leochilus Knowles & Westc. | Orchidaceae |
| Gonogona Link | Goodyera R. Br. | | | Gonogona Link | Goodyera R. Br. | Orchidaceae |
| ×Goodaleara hort. | | a | | Goodaleara hort. | | Orchidaceae |
| Goodyera R. Br. | | a | | Goodyera R. Br. | | Orchidaceae |
| Gorgoglossum F. Lehm. | Sievekingia Rchb. f. | | | Gorgoglossum F. Lehm. | Sievekingia Rchb. f. | Orchidaceae |
| Govenia Lindl. | | a | | Govenia Lindl. | | Orchidaceae |
| Govindooia Wight | Tropidia Lindl. | | | Govindooia Wight | Tropidia Lindl. | Orchidaceae |
| Gracielanthus R. González & Szlach. | Aulosepalum Garay | | | Gracielanthus R. González & Szlach. | Aulosepalum Garay | Orchidaceae |
| Grafia A. D. Hawkes | Phalaenopsis Blume | | | Grafia A. D. Hawkes | Phalaenopsis Blume | Orchidaceae |
| Grammangis Rchb. f. | | a | | Grammangis Rchb. f. | | Orchidaceae |
| Grammatophyllum Blume | | a | | Grammatophyllum Blume | | Orchidaceae |
| Grandiphyllum Docha Neto | | a | | Grandiphyllum Docha Neto | | Orchidaceae |
| Graphorkis Thouars | | a | | Graphorkis Thouars | | Orchidaceae |
| Grastidium Blume | Dendrobium Sw. | | | Grastidium Blume | Dendrobium Sw. | Orchidaceae |
| Greenwoodia Burns-Bal. | Kionophyton Garay | | | Greenwoodia Burns-Bal. | Kionophyton Garay | Orchidaceae |
| Grobya Lindl. | | a | | Grobya Lindl. | | Orchidaceae |
| Grosourdya Rchb. f. | | a | | Grosourdya Rchb. f. | | Orchidaceae |
| Grussia M. Wolff | Phalaenopsis Blume | | | Grussia M. Wolff | Phalaenopsis Blume | Orchidaceae |
| Guanchezia G. A. Romero & Carnevali | | a | | Guanchezia G. A. Romero & Carnevali | | Orchidaceae |
| Guarianthe Dressler & W. E. Higgins | | a | | Guarianthe Dressler & W. E. Higgins | | Orchidaceae |
| Gudrunia Braem | Tolumnia Raf. | | | Gudrunia Braem | Tolumnia Raf. | Orchidaceae |
| Gularia Garay | Schiedeella Schltr. | | | Gularia Garay | Schiedeella Schltr. | Orchidaceae |
| Gunnarella Senghas | | a | | Gunnarella Senghas | | Orchidaceae |
| Gunnaria S. C. Chen ex Z. J. Liu & L. J. Chen | Vanda Jones ex R. Br. | | | Gunnaria S. C. Chen ex Z. J. Liu & L. J. Chen | Vanda Jones ex R. Br. | Orchidaceae |
| Gunnarorchis Brieger | | a | | Gunnarorchis Brieger | | Orchidaceae |
| Gunnia Lindl. | Sarcochilus R. Br. | | | Gunnia Lindl. | Sarcochilus R. Br. | Orchidaceae |
| Gussonea A. Rich. | Microcoelia Lindl. | | | Gussonea A. Rich. | Microcoelia Lindl. | Orchidaceae |
| Gyaladenia Schltr. | Brachycorythis Lindl. | | | Gyaladenia Schltr. | Brachycorythis Lindl. | Orchidaceae |
| Gyalanthos Szlach. & Marg. | | a | | Gyalanthos Szlach. & Marg. | | Orchidaceae |
| Gyas Salisb. | Bletia Ruiz & Pav. | | | Gyas Salisb. | Bletia Ruiz & Pav. | Orchidaceae |
| Gymnadenia R. Br. | | a | | Gymnadenia R. Br. | | Orchidaceae |
| Gymnadeniopsis Rydb. | Platanthera Rich. | | | Gymnadeniopsis Rydb. | Platanthera Rich. | Orchidaceae |
| Gymnochilus Blume | Cheirostylis Blume | | | Gymnochilus Blume | Cheirostylis Blume | Orchidaceae |
| Gynizodon Raf. | Oncidium Sw. | | | Gynizodon Raf. | Oncidium Sw. | Orchidaceae |
| Gynoglottis J. J. Sm. | | a | | Gynoglottis J. J. Sm. | | Orchidaceae |
| Gyrostachis Blume | Spiranthes Rich. | | | Gyrostachis Blume | Spiranthes Rich. | Orchidaceae |
| Gyrostachys Pers. ex Blume | Spiranthes Rich. | | | Gyrostachys Pers. ex Blume | Spiranthes Rich. | Orchidaceae |
| Habenaria Nimmo | Habenaria Willd. | | | Habenaria Nimmo | Habenaria Willd. | Orchidaceae |
| Habenaria Willd. | | a | | Habenaria Willd. | | Orchidaceae |
| Habenella Small | Habenaria Willd. | | | Habenella Small | Habenaria Willd. | Orchidaceae |
| Habenorkis Thouars | Habenaria Willd. | | | Habenorkis Thouars | Habenaria Willd. | Orchidaceae |
| Hadrolaelia (Schltr.) Chiron & V. P. Castro | | a | | Hadrolaelia (Schltr.) Chiron & V. P. Castro | | Orchidaceae |
| Haemaria Lindl. | Goodyera R. Br. | | | Haemaria Lindl. | Goodyera R. Br. | Orchidaceae |
| Haematorchis Blume | Galeola Lour. | | | Haematorchis Blume | Galeola Lour. | Orchidaceae |
| Hagsatera R. González | | a | | Hagsatera R. González | | Orchidaceae |
| Hakoneaste F. Maek. | Ephippianthus Rchb. f. | | | Hakoneaste F. Maek. | Ephippianthus Rchb. f. | Orchidaceae |
| Halleorchis Szlach. & Olszewski | | a | | Halleorchis Szlach. & Olszewski | | Orchidaceae |
| Hammarbya Kuntze | Malaxis Sol. ex Sw. | | | Hammarbya Kuntze | Malaxis Sol. ex Sw. | Orchidaceae |
| Hamularia Aver. & Averyanova | Bulbophyllum Thouars | | | Hamularia Aver. & Averyanova | Bulbophyllum Thouars | Orchidaceae |
| Hancockia Rolfe | | a | | Hancockia Rolfe | | Orchidaceae |
| Hapalochilus (Schltr.) Senghas | Bulbophyllum Thouars | | | Hapalochilus (Schltr.) Senghas | Bulbophyllum Thouars | Orchidaceae |
| Hapalorchis Schltr. | | a | | Hapalorchis Schltr. | | Orchidaceae |
| Haplochilus Endl. | Zeuxine Lindl. | | | Haplochilus Endl. | Zeuxine Lindl. | Orchidaceae |
| Haplostellis Endl. | Nervilia Comm. ex Gaudich. | | | Haplostellis Endl. | Nervilia Comm. ex Gaudich. | Orchidaceae |
| Haraella Kudô | Gastrochilus D. Don | | | Haraella Kudô | Gastrochilus D. Don | Orchidaceae |
| Hardingia Docha Neto & Baptista | Oncidium Sw. | | | Hardingia Docha Neto & Baptista | Oncidium Sw. | Orchidaceae |
| Harrisella Fawc. & Rendle | | a | | Harrisella Fawc. & Rendle | | Orchidaceae |
| Hartwegia Lindl. | Nageliella L. O. Williams | | | Hartwegia Lindl. | Nageliella L. O. Williams | Orchidaceae |
| Hecabe Raf. | Phaius Lour. | | | Hecabe Raf. | Phaius Lour. | Orchidaceae |
| Hederorkis Thouars | | a | | Hederorkis Thouars | | Orchidaceae |
| Helcia Lindl. | Trichopilia Lindl. | | | Helcia Lindl. | Trichopilia Lindl. | Orchidaceae |
| Helictonia Ehrh. | Spiranthes Rich. | | | Helictonia Ehrh. | Spiranthes Rich. | Orchidaceae |
| Helleborine Kuntze | Calopogon R. Br. | | | Helleborine Kuntze | Calopogon R. Br. | Orchidaceae |
| Helleriella A. D. Hawkes | | a | | Helleriella A. D. Hawkes | | Orchidaceae |
| Hellerorchis A. D. Hawkes | Gomesa R. Br. | | | Hellerorchis A. D. Hawkes | Gomesa R. Br. | Orchidaceae |
| Helonoma Garay | | a | | Helonoma Garay | | Orchidaceae |
| Helorchis Schltr. | Cynorkis Thouars | | | Helorchis Schltr. | Cynorkis Thouars | Orchidaceae |
| Hemiperis Frapp. ex Cordem. | Habenaria Willd. | | | Hemiperis Frapp. ex Cordem. | Habenaria Willd. | Orchidaceae |
| Hemipilia Lindl. | | a | | Hemipilia Lindl. | | Orchidaceae |
| Hemipiliopsis Y. B. Luo & S. C. Chen | | a | | Hemipiliopsis Y. B. Luo & S. C. Chen | | Orchidaceae |
| Hemiscleria Lindl. | Epidendrum L. | | | Hemiscleria Lindl. | Epidendrum L. | Orchidaceae |
| Henosis Hook. f. | Bulbophyllum Thouars | | | Henosis Hook. f. | Bulbophyllum Thouars | Orchidaceae |
| Herminium L. | | a | | Herminium L. | | Orchidaceae |
| Herpetophytum (Schltr.) Brieger | Dendrobium Sw. | | | Herpetophytum (Schltr.) Brieger | Dendrobium Sw. | Orchidaceae |
| Herpysma Lindl. | | a | | Herpysma Lindl. | | Orchidaceae |
| Herschelia Lindl. | Disa P. J. Bergius | | | Herschelia Lindl. | Disa P. J. Bergius | Orchidaceae |
| Herschelianthe Rauschert | Disa P. J. Bergius | | | Herschelianthe Rauschert | Disa P. J. Bergius | Orchidaceae |
| Hetaeria Blume | | a | | Hetaeria Blume | | Orchidaceae |
| Heteranthocidium Szlach. et al. | Oncidium Sw. | | | Heteranthocidium Szlach. et al. | Oncidium Sw. | Orchidaceae |
| Heterotaxis Lindl. | | a | | Heterotaxis Lindl. | | Orchidaceae |
| Heterozeuxine T. Hashim. | Zeuxine Lindl. | | | Heterozeuxine T. Hashim. | Zeuxine Lindl. | Orchidaceae |
| Hexadesmia Brongn. | Scaphyglottis Poepp. & Endl. | | | Hexadesmia Brongn. | Scaphyglottis Poepp. & Endl. | Orchidaceae |
| Hexalectris Raf. | | a | | Hexalectris Raf. | | Orchidaceae |
| Hexameria R. Br. | Podochilus Blume | | | Hexameria R. Br. | Podochilus Blume | Orchidaceae |
| Hexisea Lindl. | Scaphyglottis Poepp. & Endl. | | | Hexisea Lindl. | Scaphyglottis Poepp. & Endl. | Orchidaceae |
| Hexopia Bateman ex Lindl. | Scaphyglottis Poepp. & Endl. | | | Hexopia Bateman ex Lindl. | Scaphyglottis Poepp. & Endl. | Orchidaceae |
| Himantoglossum Spreng. | | a | | Himantoglossum Spreng. | | Orchidaceae |
| Hintonella Ames | | a | | Hintonella Ames | | Orchidaceae |
| Hippeophyllum Schltr. | | a | | Hippeophyllum Schltr. | | Orchidaceae |
| Hippoglossum Breda | Bulbophyllum Thouars | | | Hippoglossum Breda | Bulbophyllum Thouars | Orchidaceae |
| Hippopodium Harv. | Ceratandra Eckl. ex F. A. Bauer | | | Hippopodium Harv. | Ceratandra Eckl. ex F. A. Bauer | Orchidaceae |
| Hipporkis Thouars | Satyrium Sw. | | | Hipporkis Thouars | Satyrium Sw. | Orchidaceae |
| Hirtzia Dodson | Pterostemma Kraenzl. | | | Hirtzia Dodson | Pterostemma Kraenzl. | Orchidaceae |
| Hispaniella Braem | Tolumnia Raf. | | | Hispaniella Braem | Tolumnia Raf. | Orchidaceae |
| Hoehneella Ruschi | | a | | Hoehneella Ruschi | | Orchidaceae |
| Hofmeistera Rchb. f. | Hofmeisterella Rchb. f. | | | Hofmeistera Rchb. f. | Hofmeisterella Rchb. f. | Orchidaceae |
| Hofmeisterella Rchb. f. | | a | | Hofmeisterella Rchb. f. | | Orchidaceae |
| Holcoglossum Schltr. | | a | | Holcoglossum Schltr. | | Orchidaceae |
| Holmesia P. J. Cribb | Angraecopsis Kraenzl. | | | Holmesia P. J. Cribb | Angraecopsis Kraenzl. | Orchidaceae |
| Hologyne Pfitzer | Coelogyne Lindl. | | | Hologyne Pfitzer | Coelogyne Lindl. | Orchidaceae |
| Holopogon Kom. & Nevski | Neottia Guett. | | | Holopogon Kom. & Nevski | Neottia Guett. | Orchidaceae |
| Holothrix Rich. ex Lindl. | | a | | Holothrix Rich. ex Lindl. | | Orchidaceae |
| Homalopetalum Rolfe | | a | | Homalopetalum Rolfe | | Orchidaceae |
| Homocolleticon (Summerh.) Szlach. & Olszewski | Cyrtorchis Schltr. | | | Homocolleticon (Summerh.) Szlach. & Olszewski | Cyrtorchis Schltr. | Orchidaceae |
| Hordeanthus Szlach. | Bulbophyllum Thouars | | | Hordeanthus Szlach. | Bulbophyllum Thouars | Orchidaceae |
| Horichia Jenny | | a | | Horichia Jenny | | Orchidaceae |
| Hormidium (Lindl.) Heynh. | Prosthechea Knowles & Westc. | | | Hormidium (Lindl.) Heynh. | Prosthechea Knowles & Westc. | Orchidaceae |
| Horvatia Garay | | a | | Horvatia Garay | | Orchidaceae |
| Houlletia Brongn. | | a | | Houlletia Brongn. | | Orchidaceae |
| Huebneria Schltr. | Orleanesia Barb. Rodr. | | | Huebneria Schltr. | Orleanesia Barb. Rodr. | Orchidaceae |
| Humboltia Ruiz & Pav. | Stelis Sw. | | | Humboltia Ruiz & Pav. | Stelis Sw. | Orchidaceae |
| Huntleya Bateman ex Lindl. | | a | | Huntleya Bateman ex Lindl. | | Orchidaceae |
| Huttonaea Harv. | | a | | Huttonaea Harv. | | Orchidaceae |
| Hyacinthorchis Blume | Cremastra Lindl. | | | Hyacinthorchis Blume | Cremastra Lindl. | Orchidaceae |
| Hyalosema Rolfe | Bulbophyllum Thouars | | | Hyalosema Rolfe | Bulbophyllum Thouars | Orchidaceae |
| Hybochilus Schltr. | Leochilus Knowles & Westc. | | | Hybochilus Schltr. | Leochilus Knowles & Westc. | Orchidaceae |
| Hydranthus Kuhl & Hasselt ex Rchb. f. | Dipodium R. Br. | | | Hydranthus Kuhl & Hasselt ex Rchb. f. | Dipodium R. Br. | Orchidaceae |
| Hydrolaelia (Schltr.) Chiron & V. P. Castro | Cattleya Lindl. | | | Hydrolaelia (Schltr.) Chiron & V. P. Castro | Cattleya Lindl. | Orchidaceae |
| Hydrorchis D. L. Jones & M. A. Clem. | | a | | Hydrorchis D. L. Jones & M. A. Clem. | | Orchidaceae |
| Hygrochilus Pfitzer | Phalaenopsis Blume | | | Hygrochilus Pfitzer | Phalaenopsis Blume | Orchidaceae |
| Hylaeorchis Carnevali & G. A. Romero | | a | | Hylaeorchis Carnevali & G. A. Romero | | Orchidaceae |
| Hylophila Lindl. | | a | | Hylophila Lindl. | | Orchidaceae |
| Hymanthoglossum Tod. | Himantoglossum Spreng. | | | Hymanthoglossum Tod. | Himantoglossum Spreng. | Orchidaceae |
| Hymeneria (Lindl.) M. A. Clem. & D. L. Jones | | a | | Hymeneria (Lindl.) M. A. Clem. & D. L. Jones | | Orchidaceae |
| Hymenochilus D. L. Jones & M. A. Clem. | | a | | Hymenochilus D. L. Jones & M. A. Clem. | | Orchidaceae |
| Hymenorchis Schltr. | | a | | Hymenorchis Schltr. | | Orchidaceae |
| Hypodema Rchb. | Cypripedium L. | | | Hypodema Rchb. | Cypripedium L. | Orchidaceae |
| Hypodematium A. Rich. | Eulophia R. Br. | | | Hypodematium A. Rich. | Eulophia R. Br. | Orchidaceae |
| Hysteria Reinw. | Corymborkis Thouars | | | Hysteria Reinw. | Corymborkis Thouars | Orchidaceae |
| Iantha Hook. | Ionopsis Kunth | | | Iantha Hook. | Ionopsis Kunth | Orchidaceae |
| Ibidium Salisb. ex House | Spiranthes Rich. | | | Ibidium Salisb. ex House | Spiranthes Rich. | Orchidaceae |
| Ichthyostomum D. L. Jones et al. | Bulbophyllum Thouars | | | Ichthyostomum D. L. Jones et al. | Bulbophyllum Thouars | Orchidaceae |
| Ida A. Ryan & Oakeley | | a | | Ida A. Ryan & Oakeley | | Orchidaceae |
| Iebine Raf. | Liparis Rich. | | | Iebine Raf. | Liparis Rich. | Orchidaceae |
| Imerinaea Schltr. | | a | | Imerinaea Schltr. | | Orchidaceae |
| India A. N. Rao | Robiquetia Gaudich. | | | India A. N. Rao | Robiquetia Gaudich. | Orchidaceae |
| Inobulbon (Schltr.) Schltr. & Kraenzl. | Dendrobium Sw. | | | Inobulbon (Schltr.) Schltr. & Kraenzl. | Dendrobium Sw. | Orchidaceae |
| Inti M. A. Blanco | | a | | Inti M. A. Blanco | | Orchidaceae |
| Ione Lindl. | Bulbophyllum Thouars | | | Ione Lindl. | Bulbophyllum Thouars | Orchidaceae |
| ×Ionocidium hort. | | a | | Ionocidium hort. | | Orchidaceae |
| Ionopsis Kunth | | a | | Ionopsis Kunth | | Orchidaceae |
| Ionorchis Beck | Limodorum Boehm. | | | Ionorchis Beck | Limodorum Boehm. | Orchidaceae |
| Ipsea Lindl. | | a | | Ipsea Lindl. | | Orchidaceae |
| Irenea Szlach. et al. | Cyrtochilum Kunth | | | Irenea Szlach. et al. | Cyrtochilum Kunth | Orchidaceae |
| Iridorchis Blume | Cymbidium Sw. | | | Iridorchis Blume | Cymbidium Sw. | Orchidaceae |
| Iridorkis Thouars | Oberonia Lindl. | | | Iridorkis Thouars | Oberonia Lindl. | Orchidaceae |
| Isabelia Barb. Rodr. | | a | | Isabelia Barb. Rodr. | | Orchidaceae |
| Ischnocentrum Schltr. | Glomera Blume | | | Ischnocentrum Schltr. | Glomera Blume | Orchidaceae |
| Ischnogyne Schltr. | | a | | Ischnogyne Schltr. | | Orchidaceae |
| Isochilostachya Mytnik & Szlach. | Polystachya Hook. | | | Isochilostachya Mytnik & Szlach. | Polystachya Hook. | Orchidaceae |
| Isochilus R. Br. | | a | | Isochilus R. Br. | | Orchidaceae |
| Isotria Raf. | | a | | Isotria Raf. | | Orchidaceae |
| Itaculumia Hoehne | Habenaria Willd. | | | Itaculumia Hoehne | Habenaria Willd. | Orchidaceae |
| Ixyophora Dressler | | a | | Ixyophora Dressler | | Orchidaceae |
| Jacquiniella Schltr. | | a | | Jacquiniella Schltr. | | Orchidaceae |
| Jamaiciella Braem | Tolumnia Raf. | | | Jamaiciella Braem | Tolumnia Raf. | Orchidaceae |
| Jansenia Barb. Rodr. | Plectrophora H. Focke | | | Jansenia Barb. Rodr. | Plectrophora H. Focke | Orchidaceae |
| Jejewoodia Szlach. | | a | | Jejewoodia Szlach. | | Orchidaceae |
| Jejosephia A. N. Rao & Mani | Bulbophyllum Thouars | | | Jejosephia A. N. Rao & Mani | Bulbophyllum Thouars | Orchidaceae |
| Jenmania Rolfe | Palmorchis Barb. Rodr. | | | Jenmania Rolfe | Palmorchis Barb. Rodr. | Orchidaceae |
| Jennyella Lückel & Fessel | Houlletia Brongn. | | | Jennyella Lückel & Fessel | Houlletia Brongn. | Orchidaceae |
| Jensoa Raf. | Cymbidium Sw. | | | Jensoa Raf. | Cymbidium Sw. | Orchidaceae |
| Jimensia Raf. | Bletilla Rchb. f. | | | Jimensia Raf. | Bletilla Rchb. f. | Orchidaceae |
| Jonesiopsis Szlach. | Caladenia R. Br. | | | Jonesiopsis Szlach. | Caladenia R. Br. | Orchidaceae |
| Josephia Wight | Sirhookera Kuntze | | | Josephia Wight | Sirhookera Kuntze | Orchidaceae |
| Jostia Luer | | a | | Jostia Luer | | Orchidaceae |
| Jouyella Szlach. | | a | | Jouyella Szlach. | | Orchidaceae |
| Jumellea Schltr. | | a | | Jumellea Schltr. | | Orchidaceae |
| Kalimantanorchis Tsukaya et al. | | a | | Kalimantanorchis Tsukaya et al. | | Orchidaceae |
| Kalimpongia Pradhan | Dickasonia L. O. Williams | | | Kalimpongia Pradhan | Dickasonia L. O. Williams | Orchidaceae |
| Kalopternix Garay & Dunst. | Epidendrum L. | | | Kalopternix Garay & Dunst. | Epidendrum L. | Orchidaceae |
| Katharinea A. D. Hawkes | Dendrobium Sw. | | | Katharinea A. D. Hawkes | Dendrobium Sw. | Orchidaceae |
| Katherinea A. D. Hawkes | Epigeneium Gagnep. | | | Katherinea A. D. Hawkes | Epigeneium Gagnep. | Orchidaceae |
| Kaurorchis D. L. Jones & M. A. Clem. | Bulbophyllum Thouars | | | Kaurorchis D. L. Jones & M. A. Clem. | Bulbophyllum Thouars | Orchidaceae |
| Kefersteinia Rchb. f. | | a | | Kefersteinia Rchb. f. | | Orchidaceae |
| Kegelia Rchb. f. | Kegeliella Mansf. | | | Kegelia Rchb. f. | Kegeliella Mansf. | Orchidaceae |
| Kegeliella Mansf. | | a | | Kegeliella Mansf. | | Orchidaceae |
| Kerigomnia P. Royen | Octarrhena Thwaites | | | Kerigomnia P. Royen | Octarrhena Thwaites | Orchidaceae |
| Kinetochilus (Schltr.) Brieger | Dendrobium Sw. | | | Kinetochilus (Schltr.) Brieger | Dendrobium Sw. | Orchidaceae |
| Kingidium P. F. Hunt | Phalaenopsis Blume | | | Kingidium P. F. Hunt | Phalaenopsis Blume | Orchidaceae |
| Kingiella Rolfe | Phalaenopsis Blume | | | Kingiella Rolfe | Phalaenopsis Blume | Orchidaceae |
| Kionophyton Garay | | a | | Kionophyton Garay | | Orchidaceae |
| Kleberiella V. P. Castro & Cath. | Gomesa R. Br. | | | Kleberiella V. P. Castro & Cath. | Gomesa R. Br. | Orchidaceae |
| Kochiophyton Schltr. ex Cogn. | Aganisia Lindl. | | | Kochiophyton Schltr. ex Cogn. | Aganisia Lindl. | Orchidaceae |
| Koellensteinia Rchb. f. | | a | | Koellensteinia Rchb. f. | | Orchidaceae |
| Konantzia Dodson & N. H. Williams | Ionopsis Kunth | | | Konantzia Dodson & N. H. Williams | Ionopsis Kunth | Orchidaceae |
| Kraenzlinella Kuntze | Pleurothallis R. Br. | | | Kraenzlinella Kuntze | Pleurothallis R. Br. | Orchidaceae |
| Kreodanthus Garay | | a | | Kreodanthus Garay | | Orchidaceae |
| Kryptostoma (Summerh.) Geerinck | Habenaria Willd. | | | Kryptostoma (Summerh.) Geerinck | Habenaria Willd. | Orchidaceae |
| Kuhlhasseltia J. J. Sm. | | a | | Kuhlhasseltia J. J. Sm. | | Orchidaceae |
| Lacaena Lindl. | | a | | Lacaena Lindl. | | Orchidaceae |
| Lacroixia Szlach. & Olszewski | Dinklageella Mansf. | | | Lacroixia Szlach. & Olszewski | Dinklageella Mansf. | Orchidaceae |
| Laelia Lindl. | | a | | Laelia Lindl. | | Orchidaceae |
| ×Laeliocatonia hort. | | a | | Laeliocatonia hort. | | Orchidaceae |
| ×Laeliocattleya Rolfe | | a | | Laeliocattleya Rolfe | | Orchidaceae |
| Laeliopsis Lindl. & Paxton | Broughtonia R. Br. | | | Laeliopsis Lindl. & Paxton | Broughtonia R. Br. | Orchidaceae |
| Lalexia Luer | Pleurothallis R. Br. | | | Lalexia Luer | Pleurothallis R. Br. | Orchidaceae |
| Lanium (Lindl.) Benth. | Epidendrum L. | | | Lanium (Lindl.) Benth. | Epidendrum L. | Orchidaceae |
| Lankesterella Ames | | a | | Lankesterella Ames | | Orchidaceae |
| Larnandra Raf. | Epidendrum L. | | | Larnandra Raf. | Epidendrum L. | Orchidaceae |
| Lathrisia Sw. | Bartholina R. Br. | | | Lathrisia Sw. | Bartholina R. Br. | Orchidaceae |
| Latourea Blume | Dendrobium Sw. | | | Latourea Blume | Dendrobium Sw. | Orchidaceae |
| Latouria Blume | Dendrobium Sw. | | | Latouria Blume | Dendrobium Sw. | Orchidaceae |
| Latourorchis Brieger | Dendrobium Sw. | | | Latourorchis Brieger | Dendrobium Sw. | Orchidaceae |
| Leaoa Schltr. & Porto | Scaphyglottis Poepp. & Endl. | | | Leaoa Schltr. & Porto | Scaphyglottis Poepp. & Endl. | Orchidaceae |
| Lecanorchis Blume | | a | | Lecanorchis Blume | | Orchidaceae |
| Lectandra J. J. Sm. | Poaephyllum Ridl. | | | Lectandra J. J. Sm. | Poaephyllum Ridl. | Orchidaceae |
| Ledgeria F. Muell. | Galeola Lour. | | | Ledgeria F. Muell. | Galeola Lour. | Orchidaceae |
| Leioanthum M. A. Clem. & D. L. Jones | Dendrobium Sw. | | | Leioanthum M. A. Clem. & D. L. Jones | Dendrobium Sw. | Orchidaceae |
| Lemboglossum Halb. | Rhynchostele Rchb. f. | | | Lemboglossum Halb. | Rhynchostele Rchb. f. | Orchidaceae |
| Lemuranthe Schltr. | Cynorkis Thouars | | | Lemuranthe Schltr. | Cynorkis Thouars | Orchidaceae |
| Lemurella Schltr. | | a | | Lemurella Schltr. | | Orchidaceae |
| Lemurorchis Kraenzl. | | a | | Lemurorchis Kraenzl. | | Orchidaceae |
| Leochilus Knowles & Westc. | | a | | Leochilus Knowles & Westc. | | Orchidaceae |
| Leopardanthus Blume | Dipodium R. Br. | | | Leopardanthus Blume | Dipodium R. Br. | Orchidaceae |
| Lepanthanthe (Schltr.) Szlach. | Bulbophyllum Thouars | | | Lepanthanthe (Schltr.) Szlach. | Bulbophyllum Thouars | Orchidaceae |
| Lepanthes Sw. | | a | | Lepanthes Sw. | | Orchidaceae |
| Lepanthopsis (Cogn.) Ames | | a | | Lepanthopsis (Cogn.) Ames | | Orchidaceae |
| Lepervenchea Cordem. | Angraecum Bory | | | Lepervenchea Cordem. | Angraecum Bory | Orchidaceae |
| Lepidogyne Blume | | a | | Lepidogyne Blume | | Orchidaceae |
| Leporella A. S. George | | a | | Leporella A. S. George | | Orchidaceae |
| Leptocentrum Schltr. | Plectrelminthus Raf. | | | Leptocentrum Schltr. | Plectrelminthus Raf. | Orchidaceae |
| Leptoceras (R. Br.) Lindl. | | a | | Leptoceras (R. Br.) Lindl. | | Orchidaceae |
| Leptogastrodia M. A. Clem. & D. L. Jones | | a | | Leptogastrodia M. A. Clem. & D. L. Jones | | Orchidaceae |
| Leptorkis Thouars | Liparis Rich. | | | Leptorkis Thouars | Liparis Rich. | Orchidaceae |
| Leptotes Lindl. | | a | | Leptotes Lindl. | | Orchidaceae |
| Lequeetia Bubani | Limodorum Boehm. | | | Lequeetia Bubani | Limodorum Boehm. | Orchidaceae |
| Lesliea Seidenf. | Phalaenopsis Blume | | | Lesliea Seidenf. | Phalaenopsis Blume | Orchidaceae |
| Leucohyle Klotzsch | Trichopilia Lindl. | | | Leucohyle Klotzsch | Trichopilia Lindl. | Orchidaceae |
| Leucolena Ridl. | Didymoplexiella Garay | | | Leucolena Ridl. | Didymoplexiella Garay | Orchidaceae |
| Leucorchis Blume | Didymoplexis Griff. | | | Leucorchis Blume | Didymoplexis Griff. | Orchidaceae |
| Leucorchis E. Mey. | Pseudorchis Ség. | | | Leucorchis E. Mey. | Pseudorchis Ség. | Orchidaceae |
| Leucostachys Hoffmanns. | Goodyera R. Br. | | | Leucostachys Hoffmanns. | Goodyera R. Br. | Orchidaceae |
| Lichinora Wight | Porpax Lindl. | | | Lichinora Wight | Porpax Lindl. | Orchidaceae |
| Ligeophila Garay | | a | | Ligeophila Garay | | Orchidaceae |
| Limatodes Blume | Calanthe R. Br. | | | Limatodes Blume | Calanthe R. Br. | Orchidaceae |
| Limnorchis Rydb. | Platanthera Rich. | | | Limnorchis Rydb. | Platanthera Rich. | Orchidaceae |
| Limodorum Boehm. | | a | | Limodorum Boehm. | | Orchidaceae |
| Lindblomia Fr. | Dactylorhiza Neck. ex Nevski | | | Lindblomia Fr. | Dactylorhiza Neck. ex Nevski | Orchidaceae |
| Lindleyella Schltr. | Rudolfiella Hoehne | | | Lindleyella Schltr. | Rudolfiella Hoehne | Orchidaceae |
| Lindsayella Ames & C. Schweinf. | Sobralia Ruiz & Pav. | | | Lindsayella Ames & C. Schweinf. | Sobralia Ruiz & Pav. | Orchidaceae |
| Linguella D. L. Jones & M. A. Clem. | | a | | Linguella D. L. Jones & M. A. Clem. | | Orchidaceae |
| Liparis Rich. | | a | | Liparis Rich. | | Orchidaceae |
| Lissochilus R. Br. | Eulophia R. Br. | | | Lissochilus R. Br. | Eulophia R. Br. | Orchidaceae |
| Listera R. Br. | Neottia Guett. | | | Listera R. Br. | Neottia Guett. | Orchidaceae |
| Listrostachys Rchb. f. | | a | | Listrostachys Rchb. f. | | Orchidaceae |
| Lobogyne Schltr. | Appendicula Blume | | | Lobogyne Schltr. | Appendicula Blume | Orchidaceae |
| Lockhartia Hook. | | a | | Lockhartia Hook. | | Orchidaceae |
| Lockia Aver. | Luisia Gaudich. | | | Lockia Aver. | Luisia Gaudich. | Orchidaceae |
| Loefgrenianthus Hoehne | | a | | Loefgrenianthus Hoehne | | Orchidaceae |
| Lonchitis Bubani | Serapias L. | | | Lonchitis Bubani | Serapias L. | Orchidaceae |
| Lophiarella Szlach. et al. | Trichocentrum Poepp. & Endl. | | | Lophiarella Szlach. et al. | Trichocentrum Poepp. & Endl. | Orchidaceae |
| Lophiaris Raf. | Trichocentrum Poepp. & Endl. | | | Lophiaris Raf. | Trichocentrum Poepp. & Endl. | Orchidaceae |
| Lophoglotis Raf. | Cattleya Lindl. | | | Lophoglotis Raf. | Cattleya Lindl. | Orchidaceae |
| Loroglossum Rich. | Himantoglossum Spreng. | | | Loroglossum Rich. | Himantoglossum Spreng. | Orchidaceae |
| Lothiania Kraenzl. | Porroglossum Schltr. | | | Lothiania Kraenzl. | Porroglossum Schltr. | Orchidaceae |
| Loxoma Garay | Smithsonia C. J. Saldanha | | | Loxoma Garay | Smithsonia C. J. Saldanha | Orchidaceae |
| Loxomorchis Rauschert | Smithsonia C. J. Saldanha | | | Loxomorchis Rauschert | Smithsonia C. J. Saldanha | Orchidaceae |
| Ludisia A. Rich. | | a | | Ludisia A. Rich. | | Orchidaceae |
| Lueckelia Jenny | | a | | Lueckelia Jenny | | Orchidaceae |
| Lueddemannia Linden & Rchb. f. | | a | | Lueddemannia Linden & Rchb. f. | | Orchidaceae |
| Lueranthos Szlach. & Marg. | | a | | Lueranthos Szlach. & Marg. | | Orchidaceae |
| Luerella Braas | Masdevallia Ruiz & Pav. | | | Luerella Braas | Masdevallia Ruiz & Pav. | Orchidaceae |
| Luisia Gaudich. | | a | | Luisia Gaudich. | | Orchidaceae |
| Luisiopsis C. S. Kumar & P. C. S. Kumar | Gastrochilus D. Don | | | Luisiopsis C. S. Kumar & P. C. S. Kumar | Gastrochilus D. Don | Orchidaceae |
| Lycaste Lindl. | | a | | Lycaste Lindl. | | Orchidaceae |
| Lycomormium Rchb. f. | | a | | Lycomormium Rchb. f. | | Orchidaceae |
| Lyperanthus R. Br. | | a | | Lyperanthus R. Br. | | Orchidaceae |
| Lyraea Lindl. | Bulbophyllum Thouars | | | Lyraea Lindl. | Bulbophyllum Thouars | Orchidaceae |
| Lyroglossa Schltr. | | a | | Lyroglossa Schltr. | | Orchidaceae |
| Lysias Salisb. ex Rydb. | Platanthera Rich. | | | Lysias Salisb. ex Rydb. | Platanthera Rich. | Orchidaceae |
| Lysiella Rydb. | Platanthera Rich. | | | Lysiella Rydb. | Platanthera Rich. | Orchidaceae |
| Lysimnia Raf. | Brassavola R. Br. | | | Lysimnia Raf. | Brassavola R. Br. | Orchidaceae |
| Maccraithea M. A. Clem. & D. L. Jones | Dendrobium Sw. | | | Maccraithea M. A. Clem. & D. L. Jones | Dendrobium Sw. | Orchidaceae |
| Macdonaldia Gunn ex Lindl. | Thelymitra J. R. Forst. & G. Forst. | | | Macdonaldia Gunn ex Lindl. | Thelymitra J. R. Forst. & G. Forst. | Orchidaceae |
| ×Maclellanara hort. | | a | | Maclellanara hort. | | Orchidaceae |
| Macodes (Blume) Lindl. | | a | | Macodes (Blume) Lindl. | | Orchidaceae |
| Macradenia R. Br. | | a | | Macradenia R. Br. | | Orchidaceae |
| Macrocentrum Phil. | Habenaria Willd. | | | Macrocentrum Phil. | Habenaria Willd. | Orchidaceae |
| Macrochilus Knowles & Westc. | Miltonia Lindl. | | | Macrochilus Knowles & Westc. | Miltonia Lindl. | Orchidaceae |
| Macroclinium Barb. Rodr. | | a | | Macroclinium Barb. Rodr. | | Orchidaceae |
| Macrolepis A. Rich. | Bulbophyllum Thouars | | | Macrolepis A. Rich. | Bulbophyllum Thouars | Orchidaceae |
| Macroplectrum Pfitzer | Angraecum Bory | | | Macroplectrum Pfitzer | Angraecum Bory | Orchidaceae |
| Macropodanthus L. O. Williams | | a | | Macropodanthus L. O. Williams | | Orchidaceae |
| Macrostomium Blume | Dendrobium Sw. | | | Macrostomium Blume | Dendrobium Sw. | Orchidaceae |
| Macrostylis Breda | Corymborkis Thouars | | | Macrostylis Breda | Corymborkis Thouars | Orchidaceae |
| Macrura (Kraenzl.) Szlach. & Sawicka | | a | | Macrura (Kraenzl.) Szlach. & Sawicka | | Orchidaceae |
| Maelenia Dumort. | Cattleya Lindl. | | | Maelenia Dumort. | Cattleya Lindl. | Orchidaceae |
| Malachadenia Lindl. | Bulbophyllum Thouars | | | Malachadenia Lindl. | Bulbophyllum Thouars | Orchidaceae |
| Malaxis Sol. ex Sw. | | a | | Malaxis Sol. ex Sw. | | Orchidaceae |
| Malleola J. J. Sm. & Schltr. | Robiquetia Gaudich. | | | Malleola J. J. Sm. & Schltr. | Robiquetia Gaudich. | Orchidaceae |
| Manniella Rchb. f. | | a | | Manniella Rchb. f. | | Orchidaceae |
| Mapinguari Carnevali & R. B. Singer | | a | | Mapinguari Carnevali & R. B. Singer | | Orchidaceae |
| Margelliantha P. J. Cribb | | a | | Margelliantha P. J. Cribb | | Orchidaceae |
| Mariarisqueta Guinea | Cheirostylis Blume | | | Mariarisqueta Guinea | Cheirostylis Blume | Orchidaceae |
| Marsupiaria Hoehne | Heterotaxis Lindl. | | | Marsupiaria Hoehne | Heterotaxis Lindl. | Orchidaceae |
| Masdevallia Ruiz & Pav. | | a | | Masdevallia Ruiz & Pav. | | Orchidaceae |
| Masdevalliantha (Luer) Szlach. & Marg. | | a | | Masdevalliantha (Luer) Szlach. & Marg. | | Orchidaceae |
| Mastigion Garay et al. | Bulbophyllum Thouars | | | Mastigion Garay et al. | Bulbophyllum Thouars | Orchidaceae |
| Maturna Raf. | Gomesa R. Br. | | | Maturna Raf. | Gomesa R. Br. | Orchidaceae |
| Maxillaria Ruiz & Pav. | | a | | Maxillaria Ruiz & Pav. | | Orchidaceae |
| Maxillariella M. A. Blanco & Carnevali | | a | | Maxillariella M. A. Blanco & Carnevali | | Orchidaceae |
| Mecosa Blume | Platanthera Rich. | | | Mecosa Blume | Platanthera Rich. | Orchidaceae |
| Mediocalcar J. J. Sm. | | a | | Mediocalcar J. J. Sm. | | Orchidaceae |
| Megaclinium Lindl. | Bulbophyllum Thouars | | | Megaclinium Lindl. | Bulbophyllum Thouars | Orchidaceae |
| Megalorchis H. Perrier | | a | | Megalorchis H. Perrier | | Orchidaceae |
| Megalotus Garay | Robiquetia Gaudich. | | | Megalotus Garay | Robiquetia Gaudich. | Orchidaceae |
| Megastylis (Schltr.) Schltr. | | a | | Megastylis (Schltr.) Schltr. | | Orchidaceae |
| Meiracyllium Rchb. f. | | a | | Meiracyllium Rchb. f. | | Orchidaceae |
| Meliclis Raf. | Coryanthes Hook. | | | Meliclis Raf. | Coryanthes Hook. | Orchidaceae |
| Menadena Raf. | Maxillaria Ruiz & Pav. | | | Menadena Raf. | Maxillaria Ruiz & Pav. | Orchidaceae |
| Menadenium Raf. | Zygosepalum Rchb. f. | | | Menadenium Raf. | Zygosepalum Rchb. f. | Orchidaceae |
| Mendoncella A. D. Hawkes | Galeottia A. Rich. | | | Mendoncella A. D. Hawkes | Galeottia A. Rich. | Orchidaceae |
| Menephora Raf. | Paphiopedilum Pfitzer | | | Menephora Raf. | Paphiopedilum Pfitzer | Orchidaceae |
| Menezesiella Chiron & V. P. Castro | Gomesa R. Br. | | | Menezesiella Chiron & V. P. Castro | Gomesa R. Br. | Orchidaceae |
| Mesadenella Pabst & Garay | | a | | Mesadenella Pabst & Garay | | Orchidaceae |
| Mesadenus Schltr. | | a | | Mesadenus Schltr. | | Orchidaceae |
| Mesoclastes Lindl. | Luisia Gaudich. | | | Mesoclastes Lindl. | Luisia Gaudich. | Orchidaceae |
| Mesodactylis Wall. | Apostasia Blume | | | Mesodactylis Wall. | Apostasia Blume | Orchidaceae |
| Mesoglossum Halb. | Rhynchostele Rchb. f. | | | Mesoglossum Halb. | Rhynchostele Rchb. f. | Orchidaceae |
| Mesoptera Raf. | Liparis Rich. | | | Mesoptera Raf. | Liparis Rich. | Orchidaceae |
| Mesospinidium Rchb. f. | Brassia R. Br. | | | Mesospinidium Rchb. f. | Brassia R. Br. | Orchidaceae |
| Metachilum Lindl. | Appendicula Blume | | | Metachilum Lindl. | Appendicula Blume | Orchidaceae |
| Mexicoa Garay | Oncidium Sw. | | | Mexicoa Garay | Oncidium Sw. | Orchidaceae |
| Mexipedium V. A. Albert & M. W. Chase | | a | | Mexipedium V. A. Albert & M. W. Chase | | Orchidaceae |
| Microchilus C. Presl | | a | | Microchilus C. Presl | | Orchidaceae |
| Microcoelia Lindl. | | a | | Microcoelia Lindl. | | Orchidaceae |
| Microepidendrum Brieger, nom. inval. | Epidendrum L. | | | Microepidendrum Brieger, nom. inval. | Epidendrum L. | Orchidaceae |
| Microholmesia P. J. Cribb | Angraecopsis Kraenzl. | | | Microholmesia P. J. Cribb | Angraecopsis Kraenzl. | Orchidaceae |
| Microlaelia (Schltr.) Chiron & V. P. Castro | | a | | Microlaelia (Schltr.) Chiron & V. P. Castro | | Orchidaceae |
| Micropera Lindl. | | a | | Micropera Lindl. | | Orchidaceae |
| Microphytanthe (Schltr.) Brieger | Dendrobium Sw. | | | Microphytanthe (Schltr.) Brieger | Dendrobium Sw. | Orchidaceae |
| Microsaccus Blume | | a | | Microsaccus Blume | | Orchidaceae |
| Microstylis (Nutt.) Eaton | Malaxis Sol. ex Sw. | | | Microstylis (Nutt.) Eaton | Malaxis Sol. ex Sw. | Orchidaceae |
| Microtatorchis Schltr. | Taeniophyllum Blume | | | Microtatorchis Schltr. | Taeniophyllum Blume | Orchidaceae |
| Microterangis (Schltr.) Senghas | Aerangis Rchb. f. | | | Microterangis (Schltr.) Senghas | Aerangis Rchb. f. | Orchidaceae |
| Microtheca Schltr. | Cynorkis Thouars | | | Microtheca Schltr. | Cynorkis Thouars | Orchidaceae |
| Microthelys Garay | | a | | Microthelys Garay | | Orchidaceae |
| Microtidium D. L. Jones & M. A. Clem. | | a | | Microtidium D. L. Jones & M. A. Clem. | | Orchidaceae |
| Microtis R. Br. | | a | | Microtis R. Br. | | Orchidaceae |
| Miguelia Aver. | | a | | Miguelia Aver. | | Orchidaceae |
| ×Miltassia hort. | ×Bratonia Moir | | | Miltassia hort. | Bratonia Moir | Orchidaceae |
| Miltonia Lindl. | | a | | Miltonia Lindl. | | Orchidaceae |
| ×Miltonidium hort. | | a | | Miltonidium hort. | | Orchidaceae |
| Miltonioides Brieger & Lückel | Oncidium Sw. | | | Miltonioides Brieger & Lückel | Oncidium Sw. | Orchidaceae |
| Miltoniopsis God.-Leb. | | a | | Miltoniopsis God.-Leb. | | Orchidaceae |
| Minicolumna Brieger, nom. inval. | Epidendrum L. | | | Minicolumna Brieger, nom. inval. | Epidendrum L. | Orchidaceae |
| Mirandopsis Szlach. & Marg. | | a | | Mirandopsis Szlach. & Marg. | | Orchidaceae |
| Mirandorchis Szlach. & Kras-Lap. | | a | | Mirandorchis Szlach. & Kras-Lap. | | Orchidaceae |
| Mischobulbon Schltr., orth. var. | Tainia Blume | | | Mischobulbon Schltr., orth. var. | Tainia Blume | Orchidaceae |
| Mischobulbum Schltr. | Tainia Blume | | | Mischobulbum Schltr. | Tainia Blume | Orchidaceae |
| Mitopetalum Blume | Tainia Blume | | | Mitopetalum Blume | Tainia Blume | Orchidaceae |
| Mitostigma Blume | Amitostigma Schltr. | | | Mitostigma Blume | Amitostigma Schltr. | Orchidaceae |
| Mobilabium Rupp | | a | | Mobilabium Rupp | | Orchidaceae |
| Moerenhoutia Blume | Platylepis A. Rich. | | | Moerenhoutia Blume | Platylepis A. Rich. | Orchidaceae |
| ×Mokara hort. | | a | | Mokara hort. | | Orchidaceae |
| Molloybas D. L. Jones & M. A. Clem. | | a | | Molloybas D. L. Jones & M. A. Clem. | | Orchidaceae |
| Monachanthus Lindl. | Catasetum Rich. ex Kunth | | | Monachanthus Lindl. | Catasetum Rich. ex Kunth | Orchidaceae |
| Monadenia Lindl. | Disa P. J. Bergius | | | Monadenia Lindl. | Disa P. J. Bergius | Orchidaceae |
| Monanthochilus (Schltr.) R. Rice | Sarcochilus R. Br. | | | Monanthochilus (Schltr.) R. Rice | Sarcochilus R. Br. | Orchidaceae |
| Monanthos (Schltr.) Brieger | Dendrobium Sw. | | | Monanthos (Schltr.) Brieger | Dendrobium Sw. | Orchidaceae |
| Monixus Finet | Angraecum Bory | | | Monixus Finet | Angraecum Bory | Orchidaceae |
| Monochilus Wall. ex Lindl. | Zeuxine Lindl. | | | Monochilus Wall. ex Lindl. | Zeuxine Lindl. | Orchidaceae |
| Monomeria Lindl. | Bulbophyllum Thouars | | | Monomeria Lindl. | Bulbophyllum Thouars | Orchidaceae |
| Monophyllorchis Schltr. | | a | | Monophyllorchis Schltr. | | Orchidaceae |
| Monorchis Agosti | Herminium L. | | | Monorchis Agosti | Herminium L. | Orchidaceae |
| Monosepalum Schltr. | Bulbophyllum Thouars | | | Monosepalum Schltr. | Bulbophyllum Thouars | Orchidaceae |
| Monotris Lindl. | Holothrix Rich. ex Lindl. | | | Monotris Lindl. | Holothrix Rich. ex Lindl. | Orchidaceae |
| Montolivaea Rchb. f. | Habenaria Willd. | | | Montolivaea Rchb. f. | Habenaria Willd. | Orchidaceae |
| Monustes Raf. | Spiranthes Rich. | | | Monustes Raf. | Spiranthes Rich. | Orchidaceae |
| Moorea Rolfe | Neomoorea Rolfe | | | Moorea Rolfe | Neomoorea Rolfe | Orchidaceae |
| Mormodes Lindl. | | a | | Mormodes Lindl. | | Orchidaceae |
| Mormolyca Fenzl | | a | | Mormolyca Fenzl | | Orchidaceae |
| Muluorchis J. J. Wood | Tropidia Lindl. | | | Muluorchis J. J. Wood | Tropidia Lindl. | Orchidaceae |
| Muscarella Luer | | a | | Muscarella Luer | | Orchidaceae |
| Myanthus Lindl. | Catasetum Rich. ex Kunth | | | Myanthus Lindl. | Catasetum Rich. ex Kunth | Orchidaceae |
| Mycaranthes Blume | Eria Lindl. | | | Mycaranthes Blume | Eria Lindl. | Orchidaceae |
| Myoda Lindl. | Ludisia A. Rich. | | | Myoda Lindl. | Ludisia A. Rich. | Orchidaceae |
| Myodium Salisb. | Ophrys L. | | | Myodium Salisb. | Ophrys L. | Orchidaceae |
| Myoxanthus Poepp. & Endl. | | a | | Myoxanthus Poepp. & Endl. | | Orchidaceae |
| Myrmechis (Lindl.) Blume | | a | | Myrmechis (Lindl.) Blume | | Orchidaceae |
| Myrmecophila Rolfe | | a | | Myrmecophila Rolfe | | Orchidaceae |
| Myrobroma Salisb. | Vanilla Mill. | | | Myrobroma Salisb. | Vanilla Mill. | Orchidaceae |
| Myrosmodes Rchb. f. | | a | | Myrosmodes Rchb. f. | | Orchidaceae |
| Mystacidium Lindl. | | a | | Mystacidium Lindl. | | Orchidaceae |
| Mystacorchis Szlach. & Marg. | | a | | Mystacorchis Szlach. & Marg. | | Orchidaceae |
| Nabaluia Ames | | a | | Nabaluia Ames | | Orchidaceae |
| Nageliella L. O. Williams | | a | | Nageliella L. O. Williams | | Orchidaceae |
| Nanodes Lindl. | Epidendrum L. | | | Nanodes Lindl. | Epidendrum L. | Orchidaceae |
| Narica Raf. | Sarcoglottis C. Presl | | | Narica Raf. | Sarcoglottis C. Presl | Orchidaceae |
| Nasonia Lindl. | Fernandezia Ruiz & Pav. | | | Nasonia Lindl. | Fernandezia Ruiz & Pav. | Orchidaceae |
| Nauenia Klotzsch | Lacaena Lindl. | | | Nauenia Klotzsch | Lacaena Lindl. | Orchidaceae |
| Neippergia C. Morren | Acineta Lindl. | | | Neippergia C. Morren | Acineta Lindl. | Orchidaceae |
| Nemacianthus D. L. Jones & M. A. Clem. | | a | | Nemacianthus D. L. Jones & M. A. Clem. | | Orchidaceae |
| Nemaconia Knowles & Westc. | Ponera Lindl. | | | Nemaconia Knowles & Westc. | Ponera Lindl. | Orchidaceae |
| Nematoceras Hook. f. | Corybas Salisb. | | | Nematoceras Hook. f. | Corybas Salisb. | Orchidaceae |
| Nemuranthes Raf. | Habenaria Willd. | | | Nemuranthes Raf. | Habenaria Willd. | Orchidaceae |
| Neobartlettia Schltr. | Palmorchis Barb. Rodr. | | | Neobartlettia Schltr. | Palmorchis Barb. Rodr. | Orchidaceae |
| Neobathiea Schltr. | | a | | Neobathiea Schltr. | | Orchidaceae |
| Neobennettia Senghas | Lockhartia Hook. | | | Neobennettia Senghas | Lockhartia Hook. | Orchidaceae |
| Neobenthamia Rolfe | Polystachya Hook. | | | Neobenthamia Rolfe | Polystachya Hook. | Orchidaceae |
| Neobolusia Schltr. | | a | | Neobolusia Schltr. | | Orchidaceae |
| Neoburttia Mytnik et al. | Polystachya Hook. | | | Neoburttia Mytnik et al. | Polystachya Hook. | Orchidaceae |
| Neoclemensia Carr | | a | | Neoclemensia Carr | | Orchidaceae |
| Neocogniauxia Schltr. | | a | | Neocogniauxia Schltr. | | Orchidaceae |
| Neocribbia Szlach. | Solenangis Schltr. | | | Neocribbia Szlach. | Solenangis Schltr. | Orchidaceae |
| Neodryas Rchb. f. | Cyrtochilum Kunth | | | Neodryas Rchb. f. | Cyrtochilum Kunth | Orchidaceae |
| Neoescobaria Garay | Trichopilia Lindl. | | | Neoescobaria Garay | Trichopilia Lindl. | Orchidaceae |
| Neofinetia Hu | Vanda Jones ex R. Br. | | | Neofinetia Hu | Vanda Jones ex R. Br. | Orchidaceae |
| Neogardneria Schltr. ex Garay | | a | | Neogardneria Schltr. ex Garay | | Orchidaceae |
| Neogyna Rchb. f. | | a | | Neogyna Rchb. f. | | Orchidaceae |
| Neogyne Rchb. f., orth. var. | Neogyna Rchb. f. | | | Neogyne Rchb. f., orth. var. | Neogyna Rchb. f. | Orchidaceae |
| Neokoehleria Schltr. | Comparettia Poepp. & Endl. | | | Neokoehleria Schltr. | Comparettia Poepp. & Endl. | Orchidaceae |
| Neolauchea Kraenzl. | Isabelia Barb. Rodr. | | | Neolauchea Kraenzl. | Isabelia Barb. Rodr. | Orchidaceae |
| Neolehmannia Kraenzl. | Epidendrum L. | | | Neolehmannia Kraenzl. | Epidendrum L. | Orchidaceae |
| Neolindleya Kraenzl. | | a | | Neolindleya Kraenzl. | | Orchidaceae |
| Neomoorea Rolfe | | a | | Neomoorea Rolfe | | Orchidaceae |
| Neoruschia Cath. & V. P. Castro | Gomesa R. Br. | | | Neoruschia Cath. & V. P. Castro | Gomesa R. Br. | Orchidaceae |
| Neotainiopsis Bennet & Raizada | Eriodes Rolfe | | | Neotainiopsis Bennet & Raizada | Eriodes Rolfe | Orchidaceae |
| Neotinea Rchb. f. | | a | | Neotinea Rchb. f. | | Orchidaceae |
| Neottia Guett. | | a | | Neottia Guett. | | Orchidaceae |
| Neottianthe (Rchb.) Schltr. | | a | | Neottianthe (Rchb.) Schltr. | | Orchidaceae |
| Neottidium Schltdl. | Neottia Guett. | | | Neottidium Schltdl. | Neottia Guett. | Orchidaceae |
| Neo-Urbania Fawc. & Rendle | Ornithidium R. Br. | | | Neo-Urbania Fawc. & Rendle | Ornithidium R. Br. | Orchidaceae |
| Neowilliamsia Garay | Epidendrum L. | | | Neowilliamsia Garay | Epidendrum L. | Orchidaceae |
| Neowolffia O. Gruss | Podangis Schltr. | | | Neowolffia O. Gruss | Podangis Schltr. | Orchidaceae |
| Nephelaphyllum Blume | Tainia Blume | | | Nephelaphyllum Blume | Tainia Blume | Orchidaceae |
| Nephrangis (Schltr.) Summerh. | | a | | Nephrangis (Schltr.) Summerh. | | Orchidaceae |
| Nephranthera Hassk. | Renanthera Lour. | | | Nephranthera Hassk. | Renanthera Lour. | Orchidaceae |
| Nerissa Raf. | Ponthieva R. Br. | | | Nerissa Raf. | Ponthieva R. Br. | Orchidaceae |
| Nervilia Comm. ex Gaudich. | | a | | Nervilia Comm. ex Gaudich. | | Orchidaceae |
| Neuwiedia Blume | | a | | Neuwiedia Blume | | Orchidaceae |
| Nidema Britton & Millsp. | | a | | Nidema Britton & Millsp. | | Orchidaceae |
| Nidus Riv. | Neottia Guett. | | | Nidus Riv. | Neottia Guett. | Orchidaceae |
| Nienokuea A. Chev. | Polystachya Hook. | | | Nienokuea A. Chev. | Polystachya Hook. | Orchidaceae |
| Nigritella Rich. | Gymnadenia R. Br. | | | Nigritella Rich. | Gymnadenia R. Br. | Orchidaceae |
| Nipponorchis Masam. | Neofinetia Hu | | | Nipponorchis Masam. | Neofinetia Hu | Orchidaceae |
| Nitidobulbon Ojeda et al. | | a | | Nitidobulbon Ojeda et al. | | Orchidaceae |
| Nohawilliamsia M. W. Chase & Whitten | | a | | Nohawilliamsia M. W. Chase & Whitten | | Orchidaceae |
| Norna Wahlenb. | Calypso Salisb. | | | Norna Wahlenb. | Calypso Salisb. | Orchidaceae |
| Notheria P. O’Byrne & J. J. Verm. | | a | | Notheria P. O’Byrne & J. J. Verm. | | Orchidaceae |
| Nothodoritis Z. H. Tsi | Phalaenopsis Blume | | | Nothodoritis Z. H. Tsi | Phalaenopsis Blume | Orchidaceae |
| Nothostele Garay | | a | | Nothostele Garay | | Orchidaceae |
| Notylia Lindl. | | a | | Notylia Lindl. | | Orchidaceae |
| Notyliopsis P. Ortíz | | a | | Notyliopsis P. Ortíz | | Orchidaceae |
| Nyctosma Raf. | Epidendrum L. | | | Nyctosma Raf. | Epidendrum L. | Orchidaceae |
| Oakes-Amesia C. Schweinf. & P. H. Allen | Ornithocephalus Hook. | | | Oakes-Amesia C. Schweinf. & P. H. Allen | Ornithocephalus Hook. | Orchidaceae |
| Oberonia Lindl. | | a | | Oberonia Lindl. | | Orchidaceae |
| Ocampoa A. Rich. & Galeotti | Cranichis Sw. | | | Ocampoa A. Rich. & Galeotti | Cranichis Sw. | Orchidaceae |
| Ochyrella Szlach. & R. González | Pteroglossa Schltr. | | | Ochyrella Szlach. & R. González | Pteroglossa Schltr. | Orchidaceae |
| Octadesmia Benth. | Dilomilis Raf. | | | Octadesmia Benth. | Dilomilis Raf. | Orchidaceae |
| Octandrorchis Brieger, nom. inval. | Octomeria R. Br. | | | Octandrorchis Brieger, nom. inval. | Octomeria R. Br. | Orchidaceae |
| Octarrhena Thwaites | | a | | Octarrhena Thwaites | | Orchidaceae |
| Octomeria R. Br. | | a | | Octomeria R. Br. | | Orchidaceae |
| Odonectis Raf. | Isotria Raf. | | | Odonectis Raf. | Isotria Raf. | Orchidaceae |
| Odontochilus Blume | | a | | Odontochilus Blume | | Orchidaceae |
| Odontoglossum Kunth | Oncidium Sw. | | | Odontoglossum Kunth | Oncidium Sw. | Orchidaceae |
| Odontorrhynchus M. N. Correa | | a | | Odontorrhynchus M. N. Correa | | Orchidaceae |
| Odontostylis Breda | Bulbophyllum Thouars | | | Odontostylis Breda | Bulbophyllum Thouars | Orchidaceae |
| Oeceoclades Lindl. | | a | | Oeceoclades Lindl. | | Orchidaceae |
| Oeonia Lindl. | | a | | Oeonia Lindl. | | Orchidaceae |
| Oeoniella Schltr. | | a | | Oeoniella Schltr. | | Orchidaceae |
| Oerstedella Rchb. f. | | a | | Oerstedella Rchb. f. | | Orchidaceae |
| Oestlundia W. E. Higgins | | a | | Oestlundia W. E. Higgins | | Orchidaceae |
| Oestlundorchis Szlach. | Deiregyne Schltr. | | | Oestlundorchis Szlach. | Deiregyne Schltr. | Orchidaceae |
| Olgasis Raf. | Tolumnia Raf. | | | Olgasis Raf. | Tolumnia Raf. | Orchidaceae |
| Oligochaetochilus Szlach. | Pterostylis R. Br. | | | Oligochaetochilus Szlach. | Pterostylis R. Br. | Orchidaceae |
| Oligophyton H. P. Linder | | a | | Oligophyton H. P. Linder | | Orchidaceae |
| Oliveriana Rchb. f. | | a | | Oliveriana Rchb. f. | | Orchidaceae |
| Ommatodium Lindl. | Pterygodium Sw. | | | Ommatodium Lindl. | Pterygodium Sw. | Orchidaceae |
| Omoea Blume | | a | | Omoea Blume | | Orchidaceae |
| ×Oncidesa hort. | | a | | Oncidesa hort. | | Orchidaceae |
| Oncidium Sw. | | a | | Oncidium Sw. | | Orchidaceae |
| ×Oncidopsis J. M. H. Shaw | | a | | Oncidopsis J. M. H. Shaw | | Orchidaceae |
| Oncodia Lindl. | Brassia R. Br. | | | Oncodia Lindl. | Brassia R. Br. | Orchidaceae |
| Oncophyllum D. L. Jones & M. A. Clem. | Bulbophyllum Thouars | | | Oncophyllum D. L. Jones & M. A. Clem. | Bulbophyllum Thouars | Orchidaceae |
| ×Oncostele J. M. H. Shaw | | a | | Oncostele J. M. H. Shaw | | Orchidaceae |
| Onkeripus Raf. | Xylobium Lindl. | | | Onkeripus Raf. | Xylobium Lindl. | Orchidaceae |
| Onychium (Blume) Blume | Dendrobium Sw. | | | Onychium (Blume) Blume | Dendrobium Sw. | Orchidaceae |
| Ophidion Luer | | a | | Ophidion Luer | | Orchidaceae |
| Ophioglossella Schuit. & Ormerod | | a | | Ophioglossella Schuit. & Ormerod | | Orchidaceae |
| Ophrys L. | | a | | Ophrys L. | | Orchidaceae |
| Orchiastrum Ség. | Spiranthes Rich. | | | Orchiastrum Ség. | Spiranthes Rich. | Orchidaceae |
| Orchidium Sw. | Calypso Salisb. | | | Orchidium Sw. | Calypso Salisb. | Orchidaceae |
| Orchidofunckia A. Rich. & Galeotti | Cryptarrhena R. Br. | | | Orchidofunckia A. Rich. & Galeotti | Cryptarrhena R. Br. | Orchidaceae |
| Orchidotypus Kraenzl. | Fernandezia Ruiz & Pav. | | | Orchidotypus Kraenzl. | Fernandezia Ruiz & Pav. | Orchidaceae |
| Orchiodes Kuntze | Goodyera R. Br. | | | Orchiodes Kuntze | Goodyera R. Br. | Orchidaceae |
| Orchipedum Breda | | a | | Orchipedum Breda | | Orchidaceae |
| Orchis L. | | a | | Orchis L. | | Orchidaceae |
| Oreorchis Lindl. | | a | | Oreorchis Lindl. | | Orchidaceae |
| Orestias Ridl. | | a | | Orestias Ridl. | | Orchidaceae |
| Orleanesia Barb. Rodr. | | a | | Orleanesia Barb. Rodr. | | Orchidaceae |
| Ormerodia Szlach. | Cleisostoma Blume | | | Ormerodia Szlach. | Cleisostoma Blume | Orchidaceae |
| Ormostema Raf. | Dendrobium Sw. | | | Ormostema Raf. | Dendrobium Sw. | Orchidaceae |
| Ornitharium Lindl. & Paxton | Pteroceras Hasselt ex Hassk. | | | Ornitharium Lindl. & Paxton | Pteroceras Hasselt ex Hassk. | Orchidaceae |
| Ornithidium R. Br. | | a | | Ornithidium R. Br. | | Orchidaceae |
| Ornithocephalus Hook. | | a | | Ornithocephalus Hook. | | Orchidaceae |
| Ornithochilus (Lindl.) Wall. ex Benth. & Hook. f. | Phalaenopsis Blume | | | Ornithochilus (Lindl.) Wall. ex Benth. & Hook. f. | Phalaenopsis Blume | Orchidaceae |
| Ornithophora Barb. Rodr. | Gomesa R. Br. | | | Ornithophora Barb. Rodr. | Gomesa R. Br. | Orchidaceae |
| Orsidice Rchb. f. | Thrixspermum Lour. | | | Orsidice Rchb. f. | Thrixspermum Lour. | Orchidaceae |
| Orthoceras R. Br. | | a | | Orthoceras R. Br. | | Orchidaceae |
| Orthochilus Hochst. ex A. Rich. | Eulophia R. Br. | | | Orthochilus Hochst. ex A. Rich. | Eulophia R. Br. | Orchidaceae |
| Orthopenthea Rolfe | Disa P. J. Bergius | | | Orthopenthea Rolfe | Disa P. J. Bergius | Orchidaceae |
| Ortmannia Opiz | Geodorum Jacks. | | | Ortmannia Opiz | Geodorum Jacks. | Orchidaceae |
| Orxera Raf. | Aerides Lour. | | | Orxera Raf. | Aerides Lour. | Orchidaceae |
| Osmoglossum (Schltr.) Schltr. | Cuitlauzina La Llave & Lex. | | | Osmoglossum (Schltr.) Schltr. | Cuitlauzina La Llave & Lex. | Orchidaceae |
| Ossiculum P. J. Cribb & Laan | | a | | Ossiculum P. J. Cribb & Laan | | Orchidaceae |
| Osyricera Blume | Bulbophyllum Thouars | | | Osyricera Blume | Bulbophyllum Thouars | Orchidaceae |
| Otandra Salisb. | Geodorum Jacks. | | | Otandra Salisb. | Geodorum Jacks. | Orchidaceae |
| Otochilus Lindl. | | a | | Otochilus Lindl. | | Orchidaceae |
| Otoglossum (Schltr.) Garay & Dunst. | | a | | Otoglossum (Schltr.) Garay & Dunst. | | Orchidaceae |
| Otopetalum Lehm. & Kraenzl. | Pleurothallis R. Br. | | | Otopetalum Lehm. & Kraenzl. | Pleurothallis R. Br. | Orchidaceae |
| Otostylis Schltr. | | a | | Otostylis Schltr. | | Orchidaceae |
| Oxyanthera Brongn. | Thelasis Blume | | | Oxyanthera Brongn. | Thelasis Blume | Orchidaceae |
| Oxyglossellum M. A. Clem. & D. L. Jones | Dendrobium Sw. | | | Oxyglossellum M. A. Clem. & D. L. Jones | Dendrobium Sw. | Orchidaceae |
| Oxysepala Wight | Bulbophyllum Thouars | | | Oxysepala Wight | Bulbophyllum Thouars | Orchidaceae |
| Oxystophyllum Blume | Dendrobium Sw. | | | Oxystophyllum Blume | Dendrobium Sw. | Orchidaceae |
| Pabstia Garay | | a | | Pabstia Garay | | Orchidaceae |
| Pabstiella Brieger & Senghas | Pleurothallis R. Br. | | | Pabstiella Brieger & Senghas | Pleurothallis R. Br. | Orchidaceae |
| Pachites Lindl. | | a | | Pachites Lindl. | | Orchidaceae |
| Pachychilus Blume | Pachystoma Blume | | | Pachychilus Blume | Pachystoma Blume | Orchidaceae |
| Pachygenium (Schltr.) Szlach. et al. | Pelexia Poit. ex Lindl. | | | Pachygenium (Schltr.) Szlach. et al. | Pelexia Poit. ex Lindl. | Orchidaceae |
| Pachyne Salisb. | Phaius Lour. | | | Pachyne Salisb. | Phaius Lour. | Orchidaceae |
| Pachyphyllum Kunth | Fernandezia Ruiz & Pav. | | | Pachyphyllum Kunth | Fernandezia Ruiz & Pav. | Orchidaceae |
| Pachyplectron Schltr. | | a | | Pachyplectron Schltr. | | Orchidaceae |
| Pachyrhizanthe (Schltr.) Nakai | Cymbidium Sw. | | | Pachyrhizanthe (Schltr.) Nakai | Cymbidium Sw. | Orchidaceae |
| Pachystele Schltr. | Scaphyglottis Poepp. & Endl. | | | Pachystele Schltr. | Scaphyglottis Poepp. & Endl. | Orchidaceae |
| Pachystelis Rauschert | Scaphyglottis Poepp. & Endl. | | | Pachystelis Rauschert | Scaphyglottis Poepp. & Endl. | Orchidaceae |
| Pachystoma Blume | | a | | Pachystoma Blume | | Orchidaceae |
| Pachystylis Blume | Pachystoma Blume | | | Pachystylis Blume | Pachystoma Blume | Orchidaceae |
| Paliris Dumort. | Liparis Rich. | | | Paliris Dumort. | Liparis Rich. | Orchidaceae |
| Palmoglossum Klotzsch ex Rchb. f. | Pleurothallis R. Br. | | | Palmoglossum Klotzsch ex Rchb. f. | Pleurothallis R. Br. | Orchidaceae |
| Palmorchis Barb. Rodr. | | a | | Palmorchis Barb. Rodr. | | Orchidaceae |
| Palumbina Rchb. f. | Cuitlauzina La Llave & Lex. | | | Palumbina Rchb. f. | Cuitlauzina La Llave & Lex. | Orchidaceae |
| Panisea (Lindl.) Lindl. | | a | | Panisea (Lindl.) Lindl. | | Orchidaceae |
| Panstrepis Raf. | Coryanthes Hook. | | | Panstrepis Raf. | Coryanthes Hook. | Orchidaceae |
| Pantlingia Prain | Stigmatodactylus Maxim. ex Makino | | | Pantlingia Prain | Stigmatodactylus Maxim. ex Makino | Orchidaceae |
| Paorchis M. C. Pace | | a | | Paorchis M. C. Pace | | Orchidaceae |
| Paphinia Lindl. | | a | | Paphinia Lindl. | | Orchidaceae |
| Paphiopedilum Pfitzer | | a | | Paphiopedilum Pfitzer | | Orchidaceae |
| Papilionanthe Schltr. | | a | | Papilionanthe Schltr. | | Orchidaceae |
| Papiliopsis É. Morren | Oncidium Sw. | | | Papiliopsis É. Morren | Oncidium Sw. | Orchidaceae |
| Papillilabium Dockrill | | a | | Papillilabium Dockrill | | Orchidaceae |
| Papperitzia Rchb. f. | Leochilus Knowles & Westc. | | | Papperitzia Rchb. f. | Leochilus Knowles & Westc. | Orchidaceae |
| Papuaea Schltr. | | a | | Papuaea Schltr. | | Orchidaceae |
| Papulipetalum (Schltr.) M. A. Clem. & D. L. Jones | Bulbophyllum Thouars | | | Papulipetalum (Schltr.) M. A. Clem. & D. L. Jones | Bulbophyllum Thouars | Orchidaceae |
| Paracalanthe Kudô | Calanthe R. Br. | | | Paracalanthe Kudô | Calanthe R. Br. | Orchidaceae |
| Paracaleana Blaxell | Caleana R. Br. | | | Paracaleana Blaxell | Caleana R. Br. | Orchidaceae |
| Paradisanthus Rchb. f. | | a | | Paradisanthus Rchb. f. | | Orchidaceae |
| Paragnathis Spreng. | Diplomeris D. Don | | | Paragnathis Spreng. | Diplomeris D. Don | Orchidaceae |
| Paraholcoglossum Z. J. Liu et al. | Holcoglossum Schltr. | | | Paraholcoglossum Z. J. Liu et al. | Holcoglossum Schltr. | Orchidaceae |
| Paralophia P. J. Cribb & Hermans | | a | | Paralophia P. J. Cribb & Hermans | | Orchidaceae |
| Parapactis W. Zimm. | Epipactis Zinn | | | Parapactis W. Zimm. | Epipactis Zinn | Orchidaceae |
| Paraphalaenopsis A. D. Hawkes | | a | | Paraphalaenopsis A. D. Hawkes | | Orchidaceae |
| Paraprasophyllum M. A. Clem. & D. L. Jones | | a | | Paraprasophyllum M. A. Clem. & D. L. Jones | | Orchidaceae |
| Parapteroceras Aver. | Tuberolabium Yamam. | | | Parapteroceras Aver. | Tuberolabium Yamam. | Orchidaceae |
| Parasarcochilus Dockrill | Sarcochilus R. Br. | | | Parasarcochilus Dockrill | Sarcochilus R. Br. | Orchidaceae |
| Parhabenaria Gagnep. | Pecteilis Raf. | | | Parhabenaria Gagnep. | Pecteilis Raf. | Orchidaceae |
| Parlatorea Barb. Rodr. | Sanderella Kuntze | | | Parlatorea Barb. Rodr. | Sanderella Kuntze | Orchidaceae |
| Pattonia Wight | Grammatophyllum Blume | | | Pattonia Wight | Grammatophyllum Blume | Orchidaceae |
| Paxtonia Lindl. | Spathoglottis Blume | | | Paxtonia Lindl. | Spathoglottis Blume | Orchidaceae |
| Pecteilis Raf. | | a | | Pecteilis Raf. | | Orchidaceae |
| Pectinaria Cordem. | Angraecum Bory | | | Pectinaria Cordem. | Angraecum Bory | Orchidaceae |
| Pedilea Lindl. | Malaxis Sol. ex Sw. | | | Pedilea Lindl. | Malaxis Sol. ex Sw. | Orchidaceae |
| Pedilochilus Schltr. | Bulbophyllum Thouars | | | Pedilochilus Schltr. | Bulbophyllum Thouars | Orchidaceae |
| Pedilonum (Blume) Blume | Dendrobium Sw. | | | Pedilonum (Blume) Blume | Dendrobium Sw. | Orchidaceae |
| Pelatantheria Ridl. | | a | | Pelatantheria Ridl. | | Orchidaceae |
| Pelexia Poit. ex Lindl. | | a | | Pelexia Poit. ex Lindl. | | Orchidaceae |
| Pelma Finet | Bulbophyllum Thouars | | | Pelma Finet | Bulbophyllum Thouars | Orchidaceae |
| Peltopus (Schltr.) Szlach. & Marg. | Bulbophyllum Thouars | | | Peltopus (Schltr.) Szlach. & Marg. | Bulbophyllum Thouars | Orchidaceae |
| Penkimia Phukan & Odyuo | Holcoglossum Schltr. | | | Penkimia Phukan & Odyuo | Holcoglossum Schltr. | Orchidaceae |
| Pennilabium J. J. Sm. | | a | | Pennilabium J. J. Sm. | | Orchidaceae |
| Penthea Lindl. | Disa P. J. Bergius | | | Penthea Lindl. | Disa P. J. Bergius | Orchidaceae |
| Pentisea (Lindl.) Szlach. | | a | | Pentisea (Lindl.) Szlach. | | Orchidaceae |
| Pentulops Raf. | Heterotaxis Lindl. | | | Pentulops Raf. | Heterotaxis Lindl. | Orchidaceae |
| Peramium Salisb. ex Coult. | Goodyera R. Br. | | | Peramium Salisb. ex Coult. | Goodyera R. Br. | Orchidaceae |
| Pergamena Finet | Dactylostalix Rchb. f. | | | Pergamena Finet | Dactylostalix Rchb. f. | Orchidaceae |
| Peristeranthus T. E. Hunt | | a | | Peristeranthus T. E. Hunt | | Orchidaceae |
| Peristeria Hook. | | a | | Peristeria Hook. | | Orchidaceae |
| Peristylus Blume | | a | | Peristylus Blume | | Orchidaceae |
| Perrieriella Schltr. | Oeonia Lindl. | | | Perrieriella Schltr. | Oeonia Lindl. | Orchidaceae |
| Perularia Lindl. | Platanthera Rich. | | | Perularia Lindl. | Platanthera Rich. | Orchidaceae |
| Pescatoria Rchb. f. | | a | | Pescatoria Rchb. f. | | Orchidaceae |
| Pesomeria Lindl. | Phaius Lour. | | | Pesomeria Lindl. | Phaius Lour. | Orchidaceae |
| Petalocentrum Schltr. | Oncidium Sw. | | | Petalocentrum Schltr. | Oncidium Sw. | Orchidaceae |
| Petalochilus R. S. Rogers | Caladenia R. Br. | | | Petalochilus R. S. Rogers | Caladenia R. Br. | Orchidaceae |
| Petrorchis D. L. Jones & M. A. Clem. | | a | | Petrorchis D. L. Jones & M. A. Clem. | | Orchidaceae |
| Pfitzeria Senghas | Comparettia Poepp. & Endl. | | | Pfitzeria Senghas | Comparettia Poepp. & Endl. | Orchidaceae |
| Phadrosanthus Neck. ex Raf. | Epidendrum L. | | | Phadrosanthus Neck. ex Raf. | Epidendrum L. | Orchidaceae |
| Phaius Lour. | | a | | Phaius Lour. | | Orchidaceae |
| Phalaenopsis Blume | | a | | Phalaenopsis Blume | | Orchidaceae |
| Phalaenopsis Blume subg. Hygrochilus | | a | i | Phalaenopsis Blume subg. Hygrochilus | | Orchidaceae |
| Phalaenopsis Blume subg. Ornithochilus | | a | i | Phalaenopsis Blume subg. Ornithochilus | | Orchidaceae |
| Phalaenopsis Blume subg. Parishianae | | a | i | Phalaenopsis Blume subg. Parishianae | | Orchidaceae |
| Phalaenopsis Blume subg. Parishianae sect. Aphyllae | | a | i | Phalaenopsis Blume subg. Parishianae sect. Aphyllae | | Orchidaceae |
| Phalaenopsis Blume subg. Parishianae sect. Deliciosae | | a | i | Phalaenopsis Blume subg. Parishianae sect. Deliciosae | | Orchidaceae |
| Phalaenopsis Blume subg. Parishianae sect. Esmeralda | | a | i | Phalaenopsis Blume subg. Parishianae sect. Esmeralda | | Orchidaceae |
| Phalaenopsis Blume subg. Parishianae sect. Parishianae | | a | i | Phalaenopsis Blume subg. Parishianae sect. Parishianae | | Orchidaceae |
| Phalaenopsis Blume subg. Phalaenopsis | | a | i | Phalaenopsis Blume subg. Phalaenopsis | | Orchidaceae |
| Phalaenopsis Blume subg. Phalaenopsis sect. Phalaenopsis | | a | i | Phalaenopsis Blume subg. Phalaenopsis sect. Phalaenopsis | | Orchidaceae |
| Phalaenopsis Blume subg. Phalaenopsis sect. Polychilos | | a | i | Phalaenopsis Blume subg. Phalaenopsis sect. Polychilos | | Orchidaceae |
| Phaniasia Blume ex Miq., nom. inval. | Habenaria Willd. | | | Phaniasia Blume ex Miq., nom. inval. | Habenaria Willd. | Orchidaceae |
| Pharochilum D. L. Jones & M. A. Clem. | Pterostylis R. Br. | | | Pharochilum D. L. Jones & M. A. Clem. | Pterostylis R. Br. | Orchidaceae |
| Pheladenia D. L. Jones & M. A. Clem. | | a | | Pheladenia D. L. Jones & M. A. Clem. | | Orchidaceae |
| Philippinaea Schltr. & Ames | Orchipedum Breda | | | Philippinaea Schltr. & Ames | Orchipedum Breda | Orchidaceae |
| Phlebochilus (Benth.) Szlach. | | a | | Phlebochilus (Benth.) Szlach. | | Orchidaceae |
| Phloeophila Hoehne & Schltr. | Pleurothallis R. Br. | | | Phloeophila Hoehne & Schltr. | Pleurothallis R. Br. | Orchidaceae |
| Pholidota Lindl. ex Hook. | | a | | Pholidota Lindl. ex Hook. | | Orchidaceae |
| Phoringopsis D. L. Jones & M. A. Clem. | Arthrochilus F. Muell. | | | Phoringopsis D. L. Jones & M. A. Clem. | Arthrochilus F. Muell. | Orchidaceae |
| Phormangis Schltr. | Ancistrorhynchus Finet | | | Phormangis Schltr. | Ancistrorhynchus Finet | Orchidaceae |
| Phragmipedium Rolfe | | a | | Phragmipedium Rolfe | | Orchidaceae |
| Phragmorchis L. O. Williams | | a | | Phragmorchis L. O. Williams | | Orchidaceae |
| Phreatia Lindl. | | a | | Phreatia Lindl. | | Orchidaceae |
| Phyllomphax Schltr. | Brachycorythis Lindl. | | | Phyllomphax Schltr. | Brachycorythis Lindl. | Orchidaceae |
| Phyllorkis Thouars | Bulbophyllum Thouars | | | Phyllorkis Thouars | Bulbophyllum Thouars | Orchidaceae |
| Phymatidium Lindl. | | a | | Phymatidium Lindl. | | Orchidaceae |
| Phymatochilum Christenson | Miltonia Lindl. | | | Phymatochilum Christenson | Miltonia Lindl. | Orchidaceae |
| Physinga Lindl. | Epidendrum L. | | | Physinga Lindl. | Epidendrum L. | Orchidaceae |
| Physoceras Schltr. | | a | | Physoceras Schltr. | | Orchidaceae |
| Physogyne Garay | | a | | Physogyne Garay | | Orchidaceae |
| Physosiphon Lindl. | Pleurothallis R. Br. | | | Physosiphon Lindl. | Pleurothallis R. Br. | Orchidaceae |
| Physothallis Garay | Pleurothallis R. Br. | | | Physothallis Garay | Pleurothallis R. Br. | Orchidaceae |
| Physurus Rich. ex Lindl. | Microchilus C. Presl | | | Physurus Rich. ex Lindl. | Microchilus C. Presl | Orchidaceae |
| Pierardia Raf. | Dendrobium Sw. | | | Pierardia Raf. | Dendrobium Sw. | Orchidaceae |
| Pilophyllum Schltr. | | a | | Pilophyllum Schltr. | | Orchidaceae |
| Pilumna Lindl. | Trichopilia Lindl. | | | Pilumna Lindl. | Trichopilia Lindl. | Orchidaceae |
| Pinalia Lindl. | Eria Lindl. | | | Pinalia Lindl. | Eria Lindl. | Orchidaceae |
| Pinelia Lindl. | | a | | Pinelia Lindl. | | Orchidaceae |
| Pinelianthe Rauschert | Pinelia Lindl. | | | Pinelianthe Rauschert | Pinelia Lindl. | Orchidaceae |
| Piperia Rydb. | Platanthera Rich. | | | Piperia Rydb. | Platanthera Rich. | Orchidaceae |
| Pittierella Schltr. | Cryptocentrum Benth. | | | Pittierella Schltr. | Cryptocentrum Benth. | Orchidaceae |
| Pityphyllum Schltr. | | a | | Pityphyllum Schltr. | | Orchidaceae |
| Placostigma Blume | Podochilus Blume | | | Placostigma Blume | Podochilus Blume | Orchidaceae |
| Platanthera Rich. | | a | | Platanthera Rich. | | Orchidaceae |
| Platyclinis Benth. | Dendrochilum Blume | | | Platyclinis Benth. | Dendrochilum Blume | Orchidaceae |
| Platycoryne Rchb. f. | | a | | Platycoryne Rchb. f. | | Orchidaceae |
| Platyglottis L. O. Williams | | a | | Platyglottis L. O. Williams | | Orchidaceae |
| Platylepis A. Rich. | | a | | Platylepis A. Rich. | | Orchidaceae |
| Platypus Small & Nash | Eulophia R. Br. | | | Platypus Small & Nash | Eulophia R. Br. | Orchidaceae |
| Platyrhiza Barb. Rodr. | | a | | Platyrhiza Barb. Rodr. | | Orchidaceae |
| Platysma Blume | Podochilus Blume | | | Platysma Blume | Podochilus Blume | Orchidaceae |
| Platystele Schltr. | | a | | Platystele Schltr. | | Orchidaceae |
| Platystylis Lindl. | Liparis Rich. | | | Platystylis Lindl. | Liparis Rich. | Orchidaceae |
| Platythelys Garay | | a | | Platythelys Garay | | Orchidaceae |
| Plectorrhiza Dockrill | | a | | Plectorrhiza Dockrill | | Orchidaceae |
| Plectrelminthus Raf. | | a | | Plectrelminthus Raf. | | Orchidaceae |
| Plectrophora H. Focke | | a | | Plectrophora H. Focke | | Orchidaceae |
| Plectrurus Raf. | Tipularia Nutt. | | | Plectrurus Raf. | Tipularia Nutt. | Orchidaceae |
| Pleione D. Don | | a | | Pleione D. Don | | Orchidaceae |
| Pleuranthium Benth. | Epidendrum L. | | | Pleuranthium Benth. | Epidendrum L. | Orchidaceae |
| Pleurobotryum Barb. Rodr. | Pleurothallis R. Br. | | | Pleurobotryum Barb. Rodr. | Pleurothallis R. Br. | Orchidaceae |
| Pleurothallis R. Br. | | a | | Pleurothallis R. Br. | | Orchidaceae |
| Pleurothallopsis Porto & Brade | Octomeria R. Br. | | | Pleurothallopsis Porto & Brade | Octomeria R. Br. | Orchidaceae |
| Plexaure Endl. | Phreatia Lindl. | | | Plexaure Endl. | Phreatia Lindl. | Orchidaceae |
| Plocoglottis Blume | | a | | Plocoglottis Blume | | Orchidaceae |
| Plumatichilos Szlach. | | a | | Plumatichilos Szlach. | | Orchidaceae |
| Poaephyllum Ridl. | | a | | Poaephyllum Ridl. | | Orchidaceae |
| Podangis Schltr. | | a | | Podangis Schltr. | | Orchidaceae |
| Podanthera Wight | Epipogium J. G. Gmel. ex Borkh. | | | Podanthera Wight | Epipogium J. G. Gmel. ex Borkh. | Orchidaceae |
| Podochilus Blume | | a | | Podochilus Blume | | Orchidaceae |
| Pogochilus Falc. | Galeola Lour. | | | Pogochilus Falc. | Galeola Lour. | Orchidaceae |
| Pogonia Juss. | | a | | Pogonia Juss. | | Orchidaceae |
| Pogoniopsis Rchb. f. | | a | | Pogoniopsis Rchb. f. | | Orchidaceae |
| Pollinirhiza Dulac | Neottia Guett. | | | Pollinirhiza Dulac | Neottia Guett. | Orchidaceae |
| Polybactrum Salisb. | Pseudorchis Ség. | | | Polybactrum Salisb. | Pseudorchis Ség. | Orchidaceae |
| Polychilos Breda | Phalaenopsis Blume | | | Polychilos Breda | Phalaenopsis Blume | Orchidaceae |
| Polycycnis Rchb. f. | | a | | Polycycnis Rchb. f. | | Orchidaceae |
| Polycycnopsis Szlach. | Polycycnis Rchb. f. | | | Polycycnopsis Szlach. | Polycycnis Rchb. f. | Orchidaceae |
| Polyotidium Garay | | a | | Polyotidium Garay | | Orchidaceae |
| Polyradicion Garay | Dendrophylax Rchb. f. | | | Polyradicion Garay | Dendrophylax Rchb. f. | Orchidaceae |
| Polyrrhiza Pfitzer | Dendrophylax Rchb. f. | | | Polyrrhiza Pfitzer | Dendrophylax Rchb. f. | Orchidaceae |
| Polystachya Hook. | | a | | Polystachya Hook. | | Orchidaceae |
| Polystylus Hasselt ex Hassk. | Phalaenopsis Blume | | | Polystylus Hasselt ex Hassk. | Phalaenopsis Blume | Orchidaceae |
| Polytoma Lour. ex Gomes | Aerides Lour. | | | Polytoma Lour. ex Gomes | Aerides Lour. | Orchidaceae |
| Pomatocalpa Breda et al. | | a | | Pomatocalpa Breda et al. | | Orchidaceae |
| Ponera Lindl. | | a | | Ponera Lindl. | | Orchidaceae |
| Ponerorchis Rchb. f. | | a | | Ponerorchis Rchb. f. | | Orchidaceae |
| Ponthieva R. Br. | | a | | Ponthieva R. Br. | | Orchidaceae |
| Porolabium Tang & F. T. Wang | | a | | Porolabium Tang & F. T. Wang | | Orchidaceae |
| Porpax Lindl. | | a | | Porpax Lindl. | | Orchidaceae |
| Porphyrodesme Schltr. | Renanthera Lour. | | | Porphyrodesme Schltr. | Renanthera Lour. | Orchidaceae |
| Porphyroglottis Ridl. | | a | | Porphyroglottis Ridl. | | Orchidaceae |
| Porphyrostachys Rchb. f. | | a | | Porphyrostachys Rchb. f. | | Orchidaceae |
| Porroglossum Schltr. | | a | | Porroglossum Schltr. | | Orchidaceae |
| Porrorhachis Garay | | a | | Porrorhachis Garay | | Orchidaceae |
| Potosia (Schltr.) R. González & Szlach. ex Mytnik | | a | | Potosia (Schltr.) R. González & Szlach. ex Mytnik | | Orchidaceae |
| Praecoxanthus Hopper & A. P. Br. | | a | | Praecoxanthus Hopper & A. P. Br. | | Orchidaceae |
| Prasophyllum R. Br. | | a | | Prasophyllum R. Br. | | Orchidaceae |
| Preptanthe Rchb. f. | Calanthe R. Br. | | | Preptanthe Rchb. f. | Calanthe R. Br. | Orchidaceae |
| Prescotia Lindl., orth. var. | Prescottia Lindl. | | | Prescotia Lindl., orth. var. | Prescottia Lindl. | Orchidaceae |
| Prescottia Lindl. | | a | | Prescottia Lindl. | | Orchidaceae |
| Pridgeonia Pupulin | | a | | Pridgeonia Pupulin | | Orchidaceae |
| Pristiglottis Cretz. & J. J. Sm. | Odontochilus Blume | | | Pristiglottis Cretz. & J. J. Sm. | Odontochilus Blume | Orchidaceae |
| Promenaea Lindl. | | a | | Promenaea Lindl. | | Orchidaceae |
| Prosthechea Knowles & Westc. | | a | | Prosthechea Knowles & Westc. | | Orchidaceae |
| Protoceras J. Joseph & Vajr. | | a | | Protoceras J. Joseph & Vajr. | | Orchidaceae |
| Pseudacoridium Ames | | a | | Pseudacoridium Ames | | Orchidaceae |
| Pseudelleanthus Brieger | Elleanthus C. Presl | | | Pseudelleanthus Brieger | Elleanthus C. Presl | Orchidaceae |
| Pseudencyclia Chiron & V. P. Castro | | a | | Pseudencyclia Chiron & V. P. Castro | | Orchidaceae |
| Pseudepidendrum Rchb. f. | Epidendrum L. | | | Pseudepidendrum Rchb. f. | Epidendrum L. | Orchidaceae |
| Pseuderia Schltr. | | a | | Pseuderia Schltr. | | Orchidaceae |
| Pseuderiopsis Rchb. f. | Eriopsis Lindl. | | | Pseuderiopsis Rchb. f. | Eriopsis Lindl. | Orchidaceae |
| Pseudocentrum Lindl. | | a | | Pseudocentrum Lindl. | | Orchidaceae |
| Pseudocoeloglossum (Szlach. & Olszewski) Szlach. | Habenaria Willd. | | | Pseudocoeloglossum (Szlach. & Olszewski) Szlach. | Habenaria Willd. | Orchidaceae |
| Pseudocranichis Garay | Galeoglossum A. Rich. & Galeotti | | | Pseudocranichis Garay | Galeoglossum A. Rich. & Galeotti | Orchidaceae |
| Pseudoctomeria Kraenzl. | Pleurothallis R. Br. | | | Pseudoctomeria Kraenzl. | Pleurothallis R. Br. | Orchidaceae |
| Pseudodiphryllum Nevski | Platanthera Rich. | | | Pseudodiphryllum Nevski | Platanthera Rich. | Orchidaceae |
| Pseudoeria (Schltr.) Schltr. | Pseuderia Schltr. | | | Pseudoeria (Schltr.) Schltr. | Pseuderia Schltr. | Orchidaceae |
| Pseudoeurystyles Hoehne | Eurystyles Wawra | | | Pseudoeurystyles Hoehne | Eurystyles Wawra | Orchidaceae |
| Pseudogoodyera Schltr. | | a | | Pseudogoodyera Schltr. | | Orchidaceae |
| Pseudohemipilia Szlach. | | a | | Pseudohemipilia Szlach. | | Orchidaceae |
| Pseudohexadesmia Brieger, nom. inval. | Scaphyglottis Poepp. & Endl. | | | Pseudohexadesmia Brieger, nom. inval. | Scaphyglottis Poepp. & Endl. | Orchidaceae |
| Pseudolaelia Porto & Brade | | a | | Pseudolaelia Porto & Brade | | Orchidaceae |
| Pseudolepanthes (Luer) Archila | | a | | Pseudolepanthes (Luer) Archila | | Orchidaceae |
| Pseudoliparis Finet | Crepidium Blume | | | Pseudoliparis Finet | Crepidium Blume | Orchidaceae |
| Pseudomacodes Rolfe | Macodes (Blume) Lindl. | | | Pseudomacodes Rolfe | Macodes (Blume) Lindl. | Orchidaceae |
| Pseudomaxillaria Hoehne | Camaridium Lindl. | | | Pseudomaxillaria Hoehne | Camaridium Lindl. | Orchidaceae |
| Pseudoperistylis Szlach. & Olszewski | Habenaria Willd. | | | Pseudoperistylis Szlach. & Olszewski | Habenaria Willd. | Orchidaceae |
| Pseudoponera Brieger, nom. inval. | Ponera Lindl. | | | Pseudoponera Brieger, nom. inval. | Ponera Lindl. | Orchidaceae |
| Pseudorchis Ség. | | a | | Pseudorchis Ség. | | Orchidaceae |
| Pseudorleanesia Rauschert | Orleanesia Barb. Rodr. | | | Pseudorleanesia Rauschert | Orleanesia Barb. Rodr. | Orchidaceae |
| Pseudostelis Schltr. | Pleurothallis R. Br. | | | Pseudostelis Schltr. | Pleurothallis R. Br. | Orchidaceae |
| Pseudovanilla Garay | | a | | Pseudovanilla Garay | | Orchidaceae |
| Psilochilus Barb. Rodr. | | a | | Psilochilus Barb. Rodr. | | Orchidaceae |
| Psittacoglossum La Llave & Lex. | Camaridium Lindl. | | | Psittacoglossum La Llave & Lex. | Camaridium Lindl. | Orchidaceae |
| Psychechilos Breda | Zeuxine Lindl. | | | Psychechilos Breda | Zeuxine Lindl. | Orchidaceae |
| Psychilis Raf. | | a | | Psychilis Raf. | | Orchidaceae |
| Psychopsiella Lückel & Braem | | a | | Psychopsiella Lückel & Braem | | Orchidaceae |
| Psychopsis Raf. | | a | | Psychopsis Raf. | | Orchidaceae |
| Psygmorchis Dodson & Dressler | Erycina Lindl. | | | Psygmorchis Dodson & Dressler | Erycina Lindl. | Orchidaceae |
| Pterichis Lindl. | | a | | Pterichis Lindl. | | Orchidaceae |
| Pteroceras Hasselt ex Hassk. | | a | | Pteroceras Hasselt ex Hassk. | | Orchidaceae |
| Pterochilus Hook. & Arn. | Crepidium Blume | | | Pterochilus Hook. & Arn. | Crepidium Blume | Orchidaceae |
| Pteroglossa Schltr. | | a | | Pteroglossa Schltr. | | Orchidaceae |
| Pteroglossaspis Rchb. f. | Eulophia R. Br. | | | Pteroglossaspis Rchb. f. | Eulophia R. Br. | Orchidaceae |
| Pterostemma Kraenzl. | | a | | Pterostemma Kraenzl. | | Orchidaceae |
| Pterostylis R. Br. | | a | | Pterostylis R. Br. | | Orchidaceae |
| Pterygodium Sw. | | a | | Pterygodium Sw. | | Orchidaceae |
| Ptilocnema D. Don | Pholidota Lindl. ex Hook. | | | Ptilocnema D. Don | Pholidota Lindl. ex Hook. | Orchidaceae |
| Ptychogyne Pfitzer | Coelogyne Lindl. | | | Ptychogyne Pfitzer | Coelogyne Lindl. | Orchidaceae |
| Pycnantha Ravenna | Malaxis Sol. ex Sw. | | | Pycnantha Ravenna | Malaxis Sol. ex Sw. | Orchidaceae |
| Pygmaeorchis Brade | | a | | Pygmaeorchis Brade | | Orchidaceae |
| Pyrorchis D. L. Jones & M. A. Clem. | | a | | Pyrorchis D. L. Jones & M. A. Clem. | | Orchidaceae |
| Quekettia Lindl. | | a | | Quekettia Lindl. | | Orchidaceae |
| Queteletia Blume | Orchipedum Breda | | | Queteletia Blume | Orchipedum Breda | Orchidaceae |
| Quisqueya Dod | | a | | Quisqueya Dod | | Orchidaceae |
| Raciborskanthos Szlach. | Cleisostoma Blume | | | Raciborskanthos Szlach. | Cleisostoma Blume | Orchidaceae |
| Radinocion Ridl. | Aerangis Rchb. f. | | | Radinocion Ridl. | Aerangis Rchb. f. | Orchidaceae |
| Ramonia Schltr. | Scaphyglottis Poepp. & Endl. | | | Ramonia Schltr. | Scaphyglottis Poepp. & Endl. | Orchidaceae |
| Ramphidia Miq. | Myrmechis (Lindl.) Blume | | | Ramphidia Miq. | Myrmechis (Lindl.) Blume | Orchidaceae |
| Rangaeris (Schltr.) Summerh. | | a | | Rangaeris (Schltr.) Summerh. | | Orchidaceae |
| Ranorchis D. L. Jones & M. A. Clem. | Pterostylis R. Br. | | | Ranorchis D. L. Jones & M. A. Clem. | Pterostylis R. Br. | Orchidaceae |
| Rauhiella Pabst & Braga | | a | | Rauhiella Pabst & Braga | | Orchidaceae |
| Raycadenco Dodson | Fernandezia Ruiz & Pav. | | | Raycadenco Dodson | Fernandezia Ruiz & Pav. | Orchidaceae |
| Regnellia Barb. Rodr. | Bletia Ruiz & Pav. | | | Regnellia Barb. Rodr. | Bletia Ruiz & Pav. | Orchidaceae |
| Reichenbachanthus Barb. Rodr. | | a | | Reichenbachanthus Barb. Rodr. | | Orchidaceae |
| ×Renantanda hort. | | a | | Renantanda hort. | | Orchidaceae |
| Renanthera Lour. | | a | | Renanthera Lour. | | Orchidaceae |
| Renantherella Ridl. | Renanthera Lour. | | | Renantherella Ridl. | Renanthera Lour. | Orchidaceae |
| Renata Ruschi | Pseudolaelia Porto & Brade | | | Renata Ruschi | Pseudolaelia Porto & Brade | Orchidaceae |
| Renzorchis Szlach. & Olszewski | | a | | Renzorchis Szlach. & Olszewski | | Orchidaceae |
| Restrepia Kunth | | a | | Restrepia Kunth | | Orchidaceae |
| Restrepiella Garay & Dunst. | | a | | Restrepiella Garay & Dunst. | | Orchidaceae |
| Restrepiopsis Luer | | a | | Restrepiopsis Luer | | Orchidaceae |
| Reymondia H. Karst. & Kuntze | Myoxanthus Poepp. & Endl. | | | Reymondia H. Karst. & Kuntze | Myoxanthus Poepp. & Endl. | Orchidaceae |
| Rhaesteria Summerh. | | a | | Rhaesteria Summerh. | | Orchidaceae |
| Rhamphidia Lindl. | Hetaeria Blume | | | Rhamphidia Lindl. | Hetaeria Blume | Orchidaceae |
| Rhamphorhynchus Garay | | a | | Rhamphorhynchus Garay | | Orchidaceae |
| Rhaphidorhynchus Finet | Aerangis Rchb. f. | | | Rhaphidorhynchus Finet | Aerangis Rchb. f. | Orchidaceae |
| Rhetinantha M. A. Blanco | | a | | Rhetinantha M. A. Blanco | | Orchidaceae |
| Rhinerrhiza Rupp | | a | | Rhinerrhiza Rupp | | Orchidaceae |
| Rhinerrhizopsis Ormerod | | a | | Rhinerrhizopsis Ormerod | | Orchidaceae |
| Rhinocerotidium Szlach. | Gomesa R. Br. | | | Rhinocerotidium Szlach. | Gomesa R. Br. | Orchidaceae |
| Rhinocidium Baptista | Gomesa R. Br. | | | Rhinocidium Baptista | Gomesa R. Br. | Orchidaceae |
| Rhipidoglossum Schltr. | | a | | Rhipidoglossum Schltr. | | Orchidaceae |
| Rhizanthella R. S. Rogers | | a | | Rhizanthella R. S. Rogers | | Orchidaceae |
| Rhomboda Lindl. | | a | | Rhomboda Lindl. | | Orchidaceae |
| Rhynchadenia A. Rich. | Macradenia R. Br. | | | Rhynchadenia A. Rich. | Macradenia R. Br. | Orchidaceae |
| Rhynchandra Rchb. f. | Corymborkis Thouars | | | Rhynchandra Rchb. f. | Corymborkis Thouars | Orchidaceae |
| Rhynchogyna Seidenf. & Garay | | a | | Rhynchogyna Seidenf. & Garay | | Orchidaceae |
| Rhyncholaelia Schltr. | | a | | Rhyncholaelia Schltr. | | Orchidaceae |
| Rhynchopera Klotzsch | Pleurothallis R. Br. | | | Rhynchopera Klotzsch | Pleurothallis R. Br. | Orchidaceae |
| Rhynchophreatia Schltr. | | a | | Rhynchophreatia Schltr. | | Orchidaceae |
| Rhynchostele Rchb. f. | | a | | Rhynchostele Rchb. f. | | Orchidaceae |
| Rhynchostylis Blume | | a | | Rhynchostylis Blume | | Orchidaceae |
| Rhytionanthos Garay et al. | Bulbophyllum Thouars | | | Rhytionanthos Garay et al. | Bulbophyllum Thouars | Orchidaceae |
| Ridleya (Hook. f.) Pfitzer | Thrixspermum Lour. | | | Ridleya (Hook. f.) Pfitzer | Thrixspermum Lour. | Orchidaceae |
| Ridleyella Schltr. | | a | | Ridleyella Schltr. | | Orchidaceae |
| Rimacola Rupp | | a | | Rimacola Rupp | | Orchidaceae |
| Risleya King & Pantl. | | a | | Risleya King & Pantl. | | Orchidaceae |
| Ritaia King & Pantl. | Ceratostylis Blume | | | Ritaia King & Pantl. | Ceratostylis Blume | Orchidaceae |
| Robiquetia Gaudich. | | a | | Robiquetia Gaudich. | | Orchidaceae |
| Rodrigoa Braas | Masdevallia Ruiz & Pav. | | | Rodrigoa Braas | Masdevallia Ruiz & Pav. | Orchidaceae |
| Rodriguezia Ruiz & Pav. | | a | | Rodriguezia Ruiz & Pav. | | Orchidaceae |
| Rodrigueziella Kuntze | Gomesa R. Br. | | | Rodrigueziella Kuntze | Gomesa R. Br. | Orchidaceae |
| Rodrigueziopsis Schltr. | Gomesa R. Br. | | | Rodrigueziopsis Schltr. | Gomesa R. Br. | Orchidaceae |
| Roeperocharis Rchb. f. | | a | | Roeperocharis Rchb. f. | | Orchidaceae |
| Roezliella Schltr. | Oncidium Sw. | | | Roezliella Schltr. | Oncidium Sw. | Orchidaceae |
| Rolfea Zahlbr. | Palmorchis Barb. Rodr. | | | Rolfea Zahlbr. | Palmorchis Barb. Rodr. | Orchidaceae |
| Rolfeella Schltr. | Benthamia A. Rich. | | | Rolfeella Schltr. | Benthamia A. Rich. | Orchidaceae |
| Rophostemon Endl., orth. var. | Nervilia Comm. ex Gaudich. | | | Rophostemon Endl., orth. var. | Nervilia Comm. ex Gaudich. | Orchidaceae |
| Roptrostemon Blume | Nervilia Comm. ex Gaudich. | | | Roptrostemon Blume | Nervilia Comm. ex Gaudich. | Orchidaceae |
| Rossioglossum (Schltr.) Garay & G. C. Kenn. | | a | | Rossioglossum (Schltr.) Garay & G. C. Kenn. | | Orchidaceae |
| Rudolfiella Hoehne | | a | | Rudolfiella Hoehne | | Orchidaceae |
| Rusbyella Rolfe | Cyrtochilum Kunth | | | Rusbyella Rolfe | Cyrtochilum Kunth | Orchidaceae |
| Rynchanthera Blume | Corymborkis Thouars | | | Rynchanthera Blume | Corymborkis Thouars | Orchidaceae |
| Saccidium Lindl. | Holothrix Rich. ex Lindl. | | | Saccidium Lindl. | Holothrix Rich. ex Lindl. | Orchidaceae |
| Saccochilus Blume | Thrixspermum Lour. | | | Saccochilus Blume | Thrixspermum Lour. | Orchidaceae |
| Saccoglossum Schltr. | Bulbophyllum Thouars | | | Saccoglossum Schltr. | Bulbophyllum Thouars | Orchidaceae |
| Saccolabiopsis J. J. Sm. | | a | | Saccolabiopsis J. J. Sm. | | Orchidaceae |
| Saccolabium Blume | | a | | Saccolabium Blume | | Orchidaceae |
| Sacodon Raf. | Cypripedium L. | | | Sacodon Raf. | Cypripedium L. | Orchidaceae |
| Sacoila Raf. | | a | | Sacoila Raf. | | Orchidaceae |
| Salacistis Rchb. f. | Goodyera R. Br. | | | Salacistis Rchb. f. | Goodyera R. Br. | Orchidaceae |
| Salpistele Dressler | | a | | Salpistele Dressler | | Orchidaceae |
| Samarorchis Ormerod | Robiquetia Gaudich. | | | Samarorchis Ormerod | Robiquetia Gaudich. | Orchidaceae |
| Sanderella Kuntze | | a | | Sanderella Kuntze | | Orchidaceae |
| Santanderella P. Ortíz | Notyliopsis P. Ortíz | | | Santanderella P. Ortíz | Notyliopsis P. Ortíz | Orchidaceae |
| Santotomasia Ormerod | | a | | Santotomasia Ormerod | | Orchidaceae |
| Sarcanthopsis Garay | | a | | Sarcanthopsis Garay | | Orchidaceae |
| Sarcanthus Lindl. | Cleisostoma Blume | | | Sarcanthus Lindl. | Cleisostoma Blume | Orchidaceae |
| Sarcobodium Beer | Bulbophyllum Thouars | | | Sarcobodium Beer | Bulbophyllum Thouars | Orchidaceae |
| Sarcocadetia (Schltr.) M. A. Clem. & D. L. Jones | Dendrobium Sw. | | | Sarcocadetia (Schltr.) M. A. Clem. & D. L. Jones | Dendrobium Sw. | Orchidaceae |
| Sarcochilus R. Br. | | a | | Sarcochilus R. Br. | | Orchidaceae |
| Sarcoglossum Beer | Cirrhaea Lindl. | | | Sarcoglossum Beer | Cirrhaea Lindl. | Orchidaceae |
| Sarcoglottis C. Presl | | a | | Sarcoglottis C. Presl | | Orchidaceae |
| Sarcoglyphis Garay | | a | | Sarcoglyphis Garay | | Orchidaceae |
| Sarcophyton Garay | | a | | Sarcophyton Garay | | Orchidaceae |
| Sarcopodium Lindl. | Dendrobium Sw. | | | Sarcopodium Lindl. | Dendrobium Sw. | Orchidaceae |
| Sarcorhynchus Schltr. | Rhipidoglossum Schltr. | | | Sarcorhynchus Schltr. | Rhipidoglossum Schltr. | Orchidaceae |
| Sarcostoma Blume | | a | | Sarcostoma Blume | | Orchidaceae |
| Sarmenticola Senghas & Garay | Macroclinium Barb. Rodr. | | | Sarmenticola Senghas & Garay | Macroclinium Barb. Rodr. | Orchidaceae |
| Sarothrochilus Schltr. | Trichoglottis Blume | | | Sarothrochilus Schltr. | Trichoglottis Blume | Orchidaceae |
| Sarracenella Luer | Pleurothallis R. Br. | | | Sarracenella Luer | Pleurothallis R. Br. | Orchidaceae |
| Satorkis Thouars | Dactylorhiza Neck. ex Nevski | | | Satorkis Thouars | Dactylorhiza Neck. ex Nevski | Orchidaceae |
| Satyridium Lindl. | Satyrium Sw. | | | Satyridium Lindl. | Satyrium Sw. | Orchidaceae |
| Satyrium Sw. | | a | | Satyrium Sw. | | Orchidaceae |
| Saundersia Rchb. f. | | a | | Saundersia Rchb. f. | | Orchidaceae |
| Sauroglossum Lindl. | | a | | Sauroglossum Lindl. | | Orchidaceae |
| Saurolophorkis Marg. & Szlach. | Crepidium Blume | | | Saurolophorkis Marg. & Szlach. | Crepidium Blume | Orchidaceae |
| Sauvetrea Szlach. | | a | | Sauvetrea Szlach. | | Orchidaceae |
| Sayeria Kraenzl. | Dendrobium Sw. | | | Sayeria Kraenzl. | Dendrobium Sw. | Orchidaceae |
| Scaphosepalum Pfitzer | | a | | Scaphosepalum Pfitzer | | Orchidaceae |
| Scaphyglottis Poepp. & Endl. | | a | | Scaphyglottis Poepp. & Endl. | | Orchidaceae |
| Scaredederis Thouars | Dendrobium Sw. | | | Scaredederis Thouars | Dendrobium Sw. | Orchidaceae |
| Scelochiloides Dodson & M. W. Chase | Comparettia Poepp. & Endl. | | | Scelochiloides Dodson & M. W. Chase | Comparettia Poepp. & Endl. | Orchidaceae |
| Scelochilopsis Dodson & M. W. Chase | Comparettia Poepp. & Endl. | | | Scelochilopsis Dodson & M. W. Chase | Comparettia Poepp. & Endl. | Orchidaceae |
| Scelochilus Klotzsch | Comparettia Poepp. & Endl. | | | Scelochilus Klotzsch | Comparettia Poepp. & Endl. | Orchidaceae |
| Schaenomorphus Thorel ex Gagnep. | Tropidia Lindl. | | | Schaenomorphus Thorel ex Gagnep. | Tropidia Lindl. | Orchidaceae |
| Schiedeella Schltr. | | a | | Schiedeella Schltr. | | Orchidaceae |
| Schismoceras C. Presl | Dendrobium Sw. | | | Schismoceras C. Presl | Dendrobium Sw. | Orchidaceae |
| Schistotylus Dockrill | | a | | Schistotylus Dockrill | | Orchidaceae |
| Schizochilus Sond. | | a | | Schizochilus Sond. | | Orchidaceae |
| Schizodium Lindl. | Disa P. J. Bergius | | | Schizodium Lindl. | Disa P. J. Bergius | Orchidaceae |
| Schizopedium Salisb. | Cypripedium L. | | | Schizopedium Salisb. | Cypripedium L. | Orchidaceae |
| Schlechterella Hoehne | Rudolfiella Hoehne | | | Schlechterella Hoehne | Rudolfiella Hoehne | Orchidaceae |
| Schlechterorchis Szlach. | | a | | Schlechterorchis Szlach. | | Orchidaceae |
| Schlimmia Planch. & Linden | | a | | Schlimmia Planch. & Linden | | Orchidaceae |
| Schoenleinia Klotzsch ex Lindl. | Ponthieva R. Br. | | | Schoenleinia Klotzsch ex Lindl. | Ponthieva R. Br. | Orchidaceae |
| Schoenomorphus Thorel ex Gagnep. | Tropidia Lindl. | | | Schoenomorphus Thorel ex Gagnep. | Tropidia Lindl. | Orchidaceae |
| Schoenorchis Reinw. | | a | | Schoenorchis Reinw. | | Orchidaceae |
| Schomburgkia Lindl. | | a | | Schomburgkia Lindl. | | Orchidaceae |
| Schuitemania Ormerod | | a | | Schuitemania Ormerod | | Orchidaceae |
| Schunkea Senghas | | a | | Schunkea Senghas | | Orchidaceae |
| Schwartzkopffia Kraenzl. | Brachycorythis Lindl. | | | Schwartzkopffia Kraenzl. | Brachycorythis Lindl. | Orchidaceae |
| Scleropteris Scheidw. | Cirrhaea Lindl. | | | Scleropteris Scheidw. | Cirrhaea Lindl. | Orchidaceae |
| Scoliochilus Rchb. f. | Appendicula Blume | | | Scoliochilus Rchb. f. | Appendicula Blume | Orchidaceae |
| Scopularia Lindl. | Holothrix Rich. ex Lindl. | | | Scopularia Lindl. | Holothrix Rich. ex Lindl. | Orchidaceae |
| Scuticaria Lindl. | | a | | Scuticaria Lindl. | | Orchidaceae |
| Sedirea Garay & H. R. Sweet | Phalaenopsis Blume | | | Sedirea Garay & H. R. Sweet | Phalaenopsis Blume | Orchidaceae |
| Seegeriella Senghas | | a | | Seegeriella Senghas | | Orchidaceae |
| Seidenfadenia Garay | | a | | Seidenfadenia Garay | | Orchidaceae |
| Seidenfadeniella C. S. Kumar | | a | | Seidenfadeniella C. S. Kumar | | Orchidaceae |
| Seidenfia Szlach. | Crepidium Blume | | | Seidenfia Szlach. | Crepidium Blume | Orchidaceae |
| Selenipedium Rchb. f. | | a | | Selenipedium Rchb. f. | | Orchidaceae |
| Semiphajus Gagnep. | Eulophia R. Br. | | | Semiphajus Gagnep. | Eulophia R. Br. | Orchidaceae |
| Senghasia Szlach. | Kefersteinia Rchb. f. | | | Senghasia Szlach. | Kefersteinia Rchb. f. | Orchidaceae |
| Senghasiella Szlach. | | a | | Senghasiella Szlach. | | Orchidaceae |
| Sepalosaccus Schltr. | Camaridium Lindl. | | | Sepalosaccus Schltr. | Camaridium Lindl. | Orchidaceae |
| Sepalosiphon Schltr. | Glomera Blume | | | Sepalosiphon Schltr. | Glomera Blume | Orchidaceae |
| Seraphyta Fisch. & C. A. Mey. | Epidendrum L. | | | Seraphyta Fisch. & C. A. Mey. | Epidendrum L. | Orchidaceae |
| Serapias L. | | a | | Serapias L. | | Orchidaceae |
| Serapiastrum Kuntze | Serapias L. | | | Serapiastrum Kuntze | Serapias L. | Orchidaceae |
| Serpenticaulis M. A. Clem. & D. L. Jones | Bulbophyllum Thouars | | | Serpenticaulis M. A. Clem. & D. L. Jones | Bulbophyllum Thouars | Orchidaceae |
| Serrastylis Rolfe | Macradenia R. Br. | | | Serrastylis Rolfe | Macradenia R. Br. | Orchidaceae |
| Sertifera Lindl. & Rchb. f. | | a | | Sertifera Lindl. & Rchb. f. | | Orchidaceae |
| Sessilibulbum Brieger, nom. inval. | Scaphyglottis Poepp. & Endl. | | | Sessilibulbum Brieger, nom. inval. | Scaphyglottis Poepp. & Endl. | Orchidaceae |
| Sestochilos Breda | Bulbophyllum Thouars | | | Sestochilos Breda | Bulbophyllum Thouars | Orchidaceae |
| Siagonanthus Poepp. & Endl. | Ornithidium R. Br. | | | Siagonanthus Poepp. & Endl. | Ornithidium R. Br. | Orchidaceae |
| Sieberia Spreng. | Platanthera Rich. | | | Sieberia Spreng. | Platanthera Rich. | Orchidaceae |
| Siederella Szlach. et al. | Cyrtochilum Kunth | | | Siederella Szlach. et al. | Cyrtochilum Kunth | Orchidaceae |
| Sievekingia Rchb. f. | | a | | Sievekingia Rchb. f. | | Orchidaceae |
| Sigmatochilus Rolfe | Chelonistele Pfitzer | | | Sigmatochilus Rolfe | Chelonistele Pfitzer | Orchidaceae |
| Sigmatogyne Pfitzer | Panisea (Lindl.) Lindl. | | | Sigmatogyne Pfitzer | Panisea (Lindl.) Lindl. | Orchidaceae |
| Sigmatostalix Rchb. f. | Oncidium Sw. | | | Sigmatostalix Rchb. f. | Oncidium Sw. | Orchidaceae |
| Silvorchis J. J. Sm. | | a | | Silvorchis J. J. Sm. | | Orchidaceae |
| Simpliglottis Szlach. | | a | | Simpliglottis Szlach. | | Orchidaceae |
| Singchia Z. J. Liu & L. J. Chen | | a | | Singchia Z. J. Liu & L. J. Chen | | Orchidaceae |
| Singularybas Molloy et al. | Corybas Salisb. | | | Singularybas Molloy et al. | Corybas Salisb. | Orchidaceae |
| Sinorchis S. C. Chen | Aphyllorchis Blume | | | Sinorchis S. C. Chen | Aphyllorchis Blume | Orchidaceae |
| Sirhookera Kuntze | | a | | Sirhookera Kuntze | | Orchidaceae |
| Sirindbornia H. A. Pedersen & Suksathan | | a | | Sirindbornia H. A. Pedersen & Suksathan | | Orchidaceae |
| Sirindhornia H. A. Pedersen & Suksathan | | a | | Sirindhornia H. A. Pedersen & Suksathan | | Orchidaceae |
| Skeptrostachys Garay | | a | | Skeptrostachys Garay | | Orchidaceae |
| Smallia Nieuwl. | Eulophia R. Br. | | | Smallia Nieuwl. | Eulophia R. Br. | Orchidaceae |
| Smithorchis Tang & F. T. Wang | | a | | Smithorchis Tang & F. T. Wang | | Orchidaceae |
| Smithsonia C. J. Saldanha | | a | | Smithsonia C. J. Saldanha | | Orchidaceae |
| Smitinandia Holttum | | a | | Smitinandia Holttum | | Orchidaceae |
| Sobennikoffia Schltr. | | a | | Sobennikoffia Schltr. | | Orchidaceae |
| Sobralia Ruiz & Pav. | | a | | Sobralia Ruiz & Pav. | | Orchidaceae |
| Sodiroella Schltr. | Telipogon Mutis ex Kunth | | | Sodiroella Schltr. | Telipogon Mutis ex Kunth | Orchidaceae |
| Solenangis Schltr. | | a | | Solenangis Schltr. | | Orchidaceae |
| Solenidiopsis Senghas | Oncidium Sw. | | | Solenidiopsis Senghas | Oncidium Sw. | Orchidaceae |
| Solenidium Lindl. | | a | | Solenidium Lindl. | | Orchidaceae |
| Solenocentrum Schltr. | | a | | Solenocentrum Schltr. | | Orchidaceae |
| ×Sophrolaelia hort. | | a | | Sophrolaelia hort. | | Orchidaceae |
| ×Sophrolaeliocattleya hort. | | a | | Sophrolaeliocattleya hort. | | Orchidaceae |
| Sophronia Lindl. | Cattleya Lindl. | | | Sophronia Lindl. | Cattleya Lindl. | Orchidaceae |
| Sophronitella Schltr. | Isabelia Barb. Rodr. | | | Sophronitella Schltr. | Isabelia Barb. Rodr. | Orchidaceae |
| Sophronitis Lindl. | Cattleya Lindl. | | | Sophronitis Lindl. | Cattleya Lindl. | Orchidaceae |
| Soterosanthus Lehm. ex Jenny | | a | | Soterosanthus Lehm. ex Jenny | | Orchidaceae |
| Spathiger Small | Epidendrum L. | | | Spathiger Small | Epidendrum L. | Orchidaceae |
| Spathoglottis Blume | | a | | Spathoglottis Blume | | Orchidaceae |
| Specklinia Lindl. | Pleurothallis R. Br. | | | Specklinia Lindl. | Pleurothallis R. Br. | Orchidaceae |
| Speculantha D. L. Jones & M. A. Clem. | Pterostylis R. Br. | | | Speculantha D. L. Jones & M. A. Clem. | Pterostylis R. Br. | Orchidaceae |
| Sphyrarhynchus Mansf. | | a | | Sphyrarhynchus Mansf. | | Orchidaceae |
| Sphyrastylis Schltr. | Ornithocephalus Hook. | | | Sphyrastylis Schltr. | Ornithocephalus Hook. | Orchidaceae |
| Spiculaea Lindl. | | a | | Spiculaea Lindl. | | Orchidaceae |
| Spilorchis D. L. Jones & M. A. Clem. | Bulbophyllum Thouars | | | Spilorchis D. L. Jones & M. A. Clem. | Bulbophyllum Thouars | Orchidaceae |
| Spiranthes Rich. | | a | | Spiranthes Rich. | | Orchidaceae |
| Spongiola J. J. Wood & A. L. Lamb | | a | | Spongiola J. J. Wood & A. L. Lamb | | Orchidaceae |
| Spuricianthus Szlach. & Marg. | | a | | Spuricianthus Szlach. & Marg. | | Orchidaceae |
| Stacyella Szlach. | Erycina Lindl. | | | Stacyella Szlach. | Erycina Lindl. | Orchidaceae |
| Stalkya Garay | | a | | Stalkya Garay | | Orchidaceae |
| Stamnorchis D. L. Jones & M. A. Clem. | Pterostylis R. Br. | | | Stamnorchis D. L. Jones & M. A. Clem. | Pterostylis R. Br. | Orchidaceae |
| Stanhopea J. Frost ex Hook. | | a | | Stanhopea J. Frost ex Hook. | | Orchidaceae |
| Stanhopeastrum Rchb. f. | Stanhopea J. Frost ex Hook. | | | Stanhopeastrum Rchb. f. | Stanhopea J. Frost ex Hook. | Orchidaceae |
| Stauritis Rchb. f. | Phalaenopsis Blume | | | Stauritis Rchb. f. | Phalaenopsis Blume | Orchidaceae |
| Staurochilus Ridl. ex Pfitzer | Trichoglottis Blume | | | Staurochilus Ridl. ex Pfitzer | Trichoglottis Blume | Orchidaceae |
| Stauroglottis Schauer | Phalaenopsis Blume | | | Stauroglottis Schauer | Phalaenopsis Blume | Orchidaceae |
| Stauropsis Rchb. f. | Trichoglottis Blume | | | Stauropsis Rchb. f. | Trichoglottis Blume | Orchidaceae |
| Stegostyla D. L. Jones & M. A. Clem. | | a | | Stegostyla D. L. Jones & M. A. Clem. | | Orchidaceae |
| Stelbophyllum M. A. Clem. & D. L. Jones | Dendrobium Sw. | | | Stelbophyllum M. A. Clem. & D. L. Jones | Dendrobium Sw. | Orchidaceae |
| Steliopsis Brieger | Stelis Sw. | | | Steliopsis Brieger | Stelis Sw. | Orchidaceae |
| Stelis Sw. | | a | | Stelis Sw. | | Orchidaceae |
| Stellilabium Schltr. | Telipogon Mutis ex Kunth | | | Stellilabium Schltr. | Telipogon Mutis ex Kunth | Orchidaceae |
| Stellorchis Thouars, orth. var. | Nervilia Comm. ex Gaudich. | | | Stellorchis Thouars, orth. var. | Nervilia Comm. ex Gaudich. | Orchidaceae |
| Stellorkis Thouars | Nervilia Comm. ex Gaudich. | | | Stellorkis Thouars | Nervilia Comm. ex Gaudich. | Orchidaceae |
| Stenia Lindl. | | a | | Stenia Lindl. | | Orchidaceae |
| Stenocoryne Lindl. | Bifrenaria Lindl. | | | Stenocoryne Lindl. | Bifrenaria Lindl. | Orchidaceae |
| Stenoglossum Kunth | Epidendrum L. | | | Stenoglossum Kunth | Epidendrum L. | Orchidaceae |
| Stenoglottis Lindl. | | a | | Stenoglottis Lindl. | | Orchidaceae |
| Stenopolen Raf. | Stenia Lindl. | | | Stenopolen Raf. | Stenia Lindl. | Orchidaceae |
| Stenoptera C. Presl | | a | | Stenoptera C. Presl | | Orchidaceae |
| Stenorrhynchos Rich. ex Spreng. | | a | | Stenorrhynchos Rich. ex Spreng. | | Orchidaceae |
| Stenotyla Dressler | | a | | Stenotyla Dressler | | Orchidaceae |
| Stephanothelys Garay | | a | | Stephanothelys Garay | | Orchidaceae |
| Stereochilus Lindl. | | a | | Stereochilus Lindl. | | Orchidaceae |
| Stereosandra Blume | | a | | Stereosandra Blume | | Orchidaceae |
| Steveniella Schltr. | | a | | Steveniella Schltr. | | Orchidaceae |
| Stevenorchis Wankow & Kraenzl. | Steveniella Schltr. | | | Stevenorchis Wankow & Kraenzl. | Steveniella Schltr. | Orchidaceae |
| Stichorkis Thouars | Liparis Rich. | | | Stichorkis Thouars | Liparis Rich. | Orchidaceae |
| Stictophyllorchis Dodson & Carnevali | Quekettia Lindl. | | | Stictophyllorchis Dodson & Carnevali | Quekettia Lindl. | Orchidaceae |
| Stictophyllum Dodson & M. W. Chase | Quekettia Lindl. | | | Stictophyllum Dodson & M. W. Chase | Quekettia Lindl. | Orchidaceae |
| Stigmatodactylus Maxim. ex Makino | | a | | Stigmatodactylus Maxim. ex Makino | | Orchidaceae |
| Stigmatorthos M. W. Chase & D. E. Benn. | Comparettia Poepp. & Endl. | | | Stigmatorthos M. W. Chase & D. E. Benn. | Comparettia Poepp. & Endl. | Orchidaceae |
| Stigmatosema Garay | Cyclopogon C. Presl | | | Stigmatosema Garay | Cyclopogon C. Presl | Orchidaceae |
| Stilbophyllum D. L. Jones & M. A. Clem. | Bulbophyllum Thouars | | | Stilbophyllum D. L. Jones & M. A. Clem. | Bulbophyllum Thouars | Orchidaceae |
| Stillifolium Königer | Trichocentrum Poepp. & Endl. | | | Stillifolium Königer | Trichocentrum Poepp. & Endl. | Orchidaceae |
| Stimegas Raf. | Cypripedium L. | | | Stimegas Raf. | Cypripedium L. | Orchidaceae |
| Stolzia Schltr. | | a | | Stolzia Schltr. | | Orchidaceae |
| Strateuma Raf. | Zeuxine Lindl. | | | Strateuma Raf. | Zeuxine Lindl. | Orchidaceae |
| Strateuma Salisb., nom. inval. | Orchis L. | | | Strateuma Salisb., nom. inval. | Orchis L. | Orchidaceae |
| Sturmia Rchb. f. | Liparis Rich. | | | Sturmia Rchb. f. | Liparis Rich. | Orchidaceae |
| Styloglossum Breda | Calanthe R. Br. | | | Styloglossum Breda | Calanthe R. Br. | Orchidaceae |
| Suarezia Dodson | | a | | Suarezia Dodson | | Orchidaceae |
| Sudamerlycaste Archila | | a | | Sudamerlycaste Archila | | Orchidaceae |
| Sulpitia Raf. | Encyclia Hook. | | | Sulpitia Raf. | Encyclia Hook. | Orchidaceae |
| Summerhayesia P. J. Cribb | | a | | Summerhayesia P. J. Cribb | | Orchidaceae |
| Sunipia Buch.-Ham. ex Sm. | Bulbophyllum Thouars | | | Sunipia Buch.-Ham. ex Sm. | Bulbophyllum Thouars | Orchidaceae |
| Sutrina Lindl. | | a | | Sutrina Lindl. | | Orchidaceae |
| Svenkoeltzia Burns-Bal. | | a | | Svenkoeltzia Burns-Bal. | | Orchidaceae |
| Sylvalismis Thouars, nom. inval. | Calanthe R. Br. | | | Sylvalismis Thouars, nom. inval. | Calanthe R. Br. | Orchidaceae |
| Symphyglossum Schltr. | Oncidium Sw. | | | Symphyglossum Schltr. | Oncidium Sw. | Orchidaceae |
| Symphyosepalum Hand.-Mazz. | | a | | Symphyosepalum Hand.-Mazz. | | Orchidaceae |
| Synadena Raf. | Phalaenopsis Blume | | | Synadena Raf. | Phalaenopsis Blume | Orchidaceae |
| Synanthes Burns-Bal. et al. | Eurystyles Wawra | | | Synanthes Burns-Bal. et al. | Eurystyles Wawra | Orchidaceae |
| Synarmosepalum Garay et al. | Bulbophyllum Thouars | | | Synarmosepalum Garay et al. | Bulbophyllum Thouars | Orchidaceae |
| Synassa Lindl. | Sauroglossum Lindl. | | | Synassa Lindl. | Sauroglossum Lindl. | Orchidaceae |
| Synoplectris Raf. | Sarcoglottis C. Presl | | | Synoplectris Raf. | Sarcoglottis C. Presl | Orchidaceae |
| Synptera Llanos | Trichoglottis Blume | | | Synptera Llanos | Trichoglottis Blume | Orchidaceae |
| Systeloglossum Schltr. | | a | | Systeloglossum Schltr. | | Orchidaceae |
| Szlachetkoella Mytnik | Polystachya Hook. | | | Szlachetkoella Mytnik | Polystachya Hook. | Orchidaceae |
| Tadeastrum Szlach. | Stanhopea J. Frost ex Hook. | | | Tadeastrum Szlach. | Stanhopea J. Frost ex Hook. | Orchidaceae |
| Taeniophyllum Blume | | a | | Taeniophyllum Blume | | Orchidaceae |
| Taeniorrhiza Summerh. | | a | | Taeniorrhiza Summerh. | | Orchidaceae |
| Tainia Blume | | a | | Tainia Blume | | Orchidaceae |
| Tainiopsis Schltr. | Eriodes Rolfe | | | Tainiopsis Schltr. | Eriodes Rolfe | Orchidaceae |
| Talpinaria H. Karst. | Pleurothallis R. Br. | | | Talpinaria H. Karst. | Pleurothallis R. Br. | Orchidaceae |
| Tangtsinia S. C. Chen | Cephalanthera Rich. | | | Tangtsinia S. C. Chen | Cephalanthera Rich. | Orchidaceae |
| Tankervillia Link | Phaius Lour. | | | Tankervillia Link | Phaius Lour. | Orchidaceae |
| Tapeinoglossum Schltr. | Bulbophyllum Thouars | | | Tapeinoglossum Schltr. | Bulbophyllum Thouars | Orchidaceae |
| Taprobanea Christenson | | a | | Taprobanea Christenson | | Orchidaceae |
| Taurantha D. L. Jones & M. A. Clem. | | a | | Taurantha D. L. Jones & M. A. Clem. | | Orchidaceae |
| Taurostalix Rchb. f. | Bulbophyllum Thouars | | | Taurostalix Rchb. f. | Bulbophyllum Thouars | Orchidaceae |
| Teagueia Luer | | a | | Teagueia Luer | | Orchidaceae |
| Telipogon Mutis ex Kunth | | a | | Telipogon Mutis ex Kunth | | Orchidaceae |
| Tetrabaculum M. A. Clem. & D. L. Jones | Dendrobium Sw. | | | Tetrabaculum M. A. Clem. & D. L. Jones | Dendrobium Sw. | Orchidaceae |
| Tetragamestus Rchb. f. | Scaphyglottis Poepp. & Endl. | | | Tetragamestus Rchb. f. | Scaphyglottis Poepp. & Endl. | Orchidaceae |
| Tetramicra Lindl. | | a | | Tetramicra Lindl. | | Orchidaceae |
| Tetrapeltis Lindl. | Otochilus Lindl. | | | Tetrapeltis Lindl. | Otochilus Lindl. | Orchidaceae |
| Tetrodon (Kraenzl.) M. A. Clem. & D. L. Jones | Dendrobium Sw. | | | Tetrodon (Kraenzl.) M. A. Clem. & D. L. Jones | Dendrobium Sw. | Orchidaceae |
| Teuscheria Garay | | a | | Teuscheria Garay | | Orchidaceae |
| Thaia Seidenf. | | a | | Thaia Seidenf. | | Orchidaceae |
| Theana Aver. | Grosourdya Rchb. f. | | | Theana Aver. | Grosourdya Rchb. f. | Orchidaceae |
| Thecopus Seidenf. | | a | | Thecopus Seidenf. | | Orchidaceae |
| Thecostele Rchb. f. | | a | | Thecostele Rchb. f. | | Orchidaceae |
| Thelasis Blume | | a | | Thelasis Blume | | Orchidaceae |
| Thelychiton Endl. | Dendrobium Sw. | | | Thelychiton Endl. | Dendrobium Sw. | Orchidaceae |
| Thelymitra J. R. Forst. & G. Forst. | | a | | Thelymitra J. R. Forst. & G. Forst. | | Orchidaceae |
| Thelyschista Garay | | a | | Thelyschista Garay | | Orchidaceae |
| Theodorea Barb. Rodr. | Gomesa R. Br. | | | Theodorea Barb. Rodr. | Gomesa R. Br. | Orchidaceae |
| Thicuania Raf. | Dendrobium Sw. | | | Thicuania Raf. | Dendrobium Sw. | Orchidaceae |
| Thiebautia Colla | Bletia Ruiz & Pav. | | | Thiebautia Colla | Bletia Ruiz & Pav. | Orchidaceae |
| Thorvaldsenia Liebm. | Chysis Lindl. | | | Thorvaldsenia Liebm. | Chysis Lindl. | Orchidaceae |
| Thrixspermum Lour. | | a | | Thrixspermum Lour. | | Orchidaceae |
| Thulinia P. J. Cribb | | a | | Thulinia P. J. Cribb | | Orchidaceae |
| Thunia Rchb. f. | | a | | Thunia Rchb. f. | | Orchidaceae |
| Thylacis Gagnep. | Thrixspermum Lour. | | | Thylacis Gagnep. | Thrixspermum Lour. | Orchidaceae |
| Thynninorchis D. L. Jones & M. A. Clem. | Drakaea Lindl. | | | Thynninorchis D. L. Jones & M. A. Clem. | Drakaea Lindl. | Orchidaceae |
| Thysanochilus Falc. | Eulophia R. Br. | | | Thysanochilus Falc. | Eulophia R. Br. | Orchidaceae |
| Thysanoglossa Porto & Brade | | a | | Thysanoglossa Porto & Brade | | Orchidaceae |
| Ticoglossum Lucas Rodr. ex Halb. | Rossioglossum (Schltr.) Garay & G. C. Kenn. | | | Ticoglossum Lucas Rodr. ex Halb. | Rossioglossum (Schltr.) Garay & G. C. Kenn. | Orchidaceae |
| Tinea Biv. | Neotinea Rchb. f. | | | Tinea Biv. | Neotinea Rchb. f. | Orchidaceae |
| Tipularia Nutt. | | a | | Tipularia Nutt. | | Orchidaceae |
| Titania Endl. | Oberonia Lindl. | | | Titania Endl. | Oberonia Lindl. | Orchidaceae |
| Todaroa A. Rich. & Galeotti | Campylocentrum Benth. | | | Todaroa A. Rich. & Galeotti | Campylocentrum Benth. | Orchidaceae |
| Tolumnia Raf. | | a | | Tolumnia Raf. | | Orchidaceae |
| Tomotris Raf. | Corymborkis Thouars | | | Tomotris Raf. | Corymborkis Thouars | Orchidaceae |
| Townsonia Cheeseman | | a | | Townsonia Cheeseman | | Orchidaceae |
| Trachelosiphon Schltr. | Eurystyles Wawra | | | Trachelosiphon Schltr. | Eurystyles Wawra | Orchidaceae |
| Trachoma Garay | | a | | Trachoma Garay | | Orchidaceae |
| Trachypetalum Szlach. & Sawicka | | a | | Trachypetalum Szlach. & Sawicka | | Orchidaceae |
| Trachyrhachis (Schltr.) Szlach. | Bulbophyllum Thouars | | | Trachyrhachis (Schltr.) Szlach. | Bulbophyllum Thouars | Orchidaceae |
| Trachyrhizum (Schltr.) Brieger | Dendrobium Sw. | | | Trachyrhizum (Schltr.) Brieger | Dendrobium Sw. | Orchidaceae |
| Traunsteinera Rchb. | | a | | Traunsteinera Rchb. | | Orchidaceae |
| Trevoria F. Lehm. | | a | | Trevoria F. Lehm. | | Orchidaceae |
| Triaristella (Rchb.) Brieger ex Luer | Trisetella Luer | | | Triaristella (Rchb.) Brieger ex Luer | Trisetella Luer | Orchidaceae |
| Triaristella Brieger, nom. inval. | Trisetella Luer | | | Triaristella Brieger, nom. inval. | Trisetella Luer | Orchidaceae |
| Triaristellina Rauschert | Trisetella Luer | | | Triaristellina Rauschert | Trisetella Luer | Orchidaceae |
| Trias Lindl. | Bulbophyllum Thouars | | | Trias Lindl. | Bulbophyllum Thouars | Orchidaceae |
| Tribrachia Lindl. | Bulbophyllum Thouars | | | Tribrachia Lindl. | Bulbophyllum Thouars | Orchidaceae |
| Triceratorhynchus Summerh. | | a | | Triceratorhynchus Summerh. | | Orchidaceae |
| Trichocentrum Poepp. & Endl. | | a | | Trichocentrum Poepp. & Endl. | | Orchidaceae |
| Trichoceros Kunth | | a | | Trichoceros Kunth | | Orchidaceae |
| Trichochilus Ames | Dipodium R. Br. | | | Trichochilus Ames | Dipodium R. Br. | Orchidaceae |
| Trichoglottis Blume | | a | | Trichoglottis Blume | | Orchidaceae |
| Trichopilia Lindl. | | a | | Trichopilia Lindl. | | Orchidaceae |
| Trichosalpinx Luer | | a | | Trichosalpinx Luer | | Orchidaceae |
| Trichosia Blume | Eria Lindl. | | | Trichosia Blume | Eria Lindl. | Orchidaceae |
| Trichosma Lindl. | Eria Lindl. | | | Trichosma Lindl. | Eria Lindl. | Orchidaceae |
| Trichotosia Blume | | a | | Trichotosia Blume | | Orchidaceae |
| Tridactyle Schltr. | | a | | Tridactyle Schltr. | | Orchidaceae |
| Trigonanthe (Schltr.) Brieger, nom. inval. | Dryadella Luer | | | Trigonanthe (Schltr.) Brieger, nom. inval. | Dryadella Luer | Orchidaceae |
| Trigonidium Lindl. | | a | | Trigonidium Lindl. | | Orchidaceae |
| Trigonochilum Königer & Schildh. | Cyrtochilum Kunth | | | Trigonochilum Königer & Schildh. | Cyrtochilum Kunth | Orchidaceae |
| Triorchis Agosti | Spiranthes Rich. | | | Triorchis Agosti | Spiranthes Rich. | Orchidaceae |
| Triorchos Small & Nash | Eulophia R. Br. | | | Triorchos Small & Nash | Eulophia R. Br. | Orchidaceae |
| Triphora Nutt. | | a | | Triphora Nutt. | | Orchidaceae |
| Tripleura Lindl. | Zeuxine Lindl. | | | Tripleura Lindl. | Zeuxine Lindl. | Orchidaceae |
| Triplorhiza Ehrh. | Pseudorchis Ség. | | | Triplorhiza Ehrh. | Pseudorchis Ség. | Orchidaceae |
| Tripudianthes (Seidenf.) Szlach. & Kras | Bulbophyllum Thouars | | | Tripudianthes (Seidenf.) Szlach. & Kras | Bulbophyllum Thouars | Orchidaceae |
| Trisetella Luer | | a | | Trisetella Luer | | Orchidaceae |
| Tritelandra Raf. | Epidendrum L. | | | Tritelandra Raf. | Epidendrum L. | Orchidaceae |
| Trizeuxis Lindl. | | a | | Trizeuxis Lindl. | | Orchidaceae |
| Trophianthus Scheidw. | Aspasia Lindl. | | | Trophianthus Scheidw. | Aspasia Lindl. | Orchidaceae |
| Tropidia Lindl. | | a | | Tropidia Lindl. | | Orchidaceae |
| Tropilis Raf. | Dendrobium Sw. | | | Tropilis Raf. | Dendrobium Sw. | Orchidaceae |
| Trudelia Garay | Vanda Jones ex R. Br. | | | Trudelia Garay | Vanda Jones ex R. Br. | Orchidaceae |
| Tryphia Lindl. | Holothrix Rich. ex Lindl. | | | Tryphia Lindl. | Holothrix Rich. ex Lindl. | Orchidaceae |
| Tsaiorchis Tang & F. T. Wang | Diphylax Hook. f. | | | Tsaiorchis Tang & F. T. Wang | Diphylax Hook. f. | Orchidaceae |
| Tsiorchis Z. J. Liu et al. | Holcoglossum Schltr. | | | Tsiorchis Z. J. Liu et al. | Holcoglossum Schltr. | Orchidaceae |
| Tubella (Luer) Archila | | a | | Tubella (Luer) Archila | | Orchidaceae |
| Tuberolabium Yamam. | | a | | Tuberolabium Yamam. | | Orchidaceae |
| Tubilabium J. J. Sm. | Myrmechis (Lindl.) Blume | | | Tubilabium J. J. Sm. | Myrmechis (Lindl.) Blume | Orchidaceae |
| Tulexis Raf. | Brassavola R. Br. | | | Tulexis Raf. | Brassavola R. Br. | Orchidaceae |
| Tulotis Raf. | Platanthera Rich. | | | Tulotis Raf. | Platanthera Rich. | Orchidaceae |
| Tussaca Raf. | Goodyera R. Br. | | | Tussaca Raf. | Goodyera R. Br. | Orchidaceae |
| Tylochilus Nees | Cyrtopodium R. Br. | | | Tylochilus Nees | Cyrtopodium R. Br. | Orchidaceae |
| Tylostigma Schltr. | | a | | Tylostigma Schltr. | | Orchidaceae |
| Tylostylis Blume | Eria Lindl. | | | Tylostylis Blume | Eria Lindl. | Orchidaceae |
| Ulantha Hook. | Chloraea Lindl. | | | Ulantha Hook. | Chloraea Lindl. | Orchidaceae |
| Uleiorchis Hoehne | | a | | Uleiorchis Hoehne | | Orchidaceae |
| Uncifera Lindl. | | a | | Uncifera Lindl. | | Orchidaceae |
| Unguiculabia Mytnik & Szlach. | Polystachya Hook. | | | Unguiculabia Mytnik & Szlach. | Polystachya Hook. | Orchidaceae |
| Urochilus D. L. Jones & M. A. Clem. | Pterostylis R. Br. | | | Urochilus D. L. Jones & M. A. Clem. | Pterostylis R. Br. | Orchidaceae |
| Uropedium Lindl. | Phragmipedium Rolfe | | | Uropedium Lindl. | Phragmipedium Rolfe | Orchidaceae |
| Urostachya (Lindl.) Brieger | Eria Lindl. | | | Urostachya (Lindl.) Brieger | Eria Lindl. | Orchidaceae |
| Vanda Jones ex R. Br. | | a | | Vanda Jones ex R. Br. | | Orchidaceae |
| ×Vandaenopsis Guillaumin | | a | | Vandaenopsis Guillaumin | | Orchidaceae |
| Vandopsis Pfitzer | | a | | Vandopsis Pfitzer | | Orchidaceae |
| Vanilla Mill. | | a | | Vanilla Mill. | | Orchidaceae |
| Vappodes M. A. Clem. & D. L. Jones | Dendrobium Sw. | | | Vappodes M. A. Clem. & D. L. Jones | Dendrobium Sw. | Orchidaceae |
| Vargasiella C. Schweinf. | | a | | Vargasiella C. Schweinf. | | Orchidaceae |
| Vasqueziella Dodson | | a | | Vasqueziella Dodson | | Orchidaceae |
| Ventricularia Garay | Trichoglottis Blume | | | Ventricularia Garay | Trichoglottis Blume | Orchidaceae |
| Vesicisepalum (J. J. Sm.) Garay et al. | Bulbophyllum Thouars | | | Vesicisepalum (J. J. Sm.) Garay et al. | Bulbophyllum Thouars | Orchidaceae |
| Vexillabium F. Maek. | Kuhlhasseltia J. J. Sm. | | | Vexillabium F. Maek. | Kuhlhasseltia J. J. Sm. | Orchidaceae |
| Veyretella Szlach. & Olszewski | | a | | Veyretella Szlach. & Olszewski | | Orchidaceae |
| Veyretia Szlach. | | a | | Veyretia Szlach. | | Orchidaceae |
| Vieillardorchis Kraenzl. | Goodyera R. Br. | | | Vieillardorchis Kraenzl. | Goodyera R. Br. | Orchidaceae |
| Vietorchis Aver. & Averyanova | Silvorchis J. J. Sm. | | | Vietorchis Aver. & Averyanova | Silvorchis J. J. Sm. | Orchidaceae |
| Vitekorchis Romowicz & Szlach. | | a | | Vitekorchis Romowicz & Szlach. | | Orchidaceae |
| Vonroemeria J. J. Sm. | Octarrhena Thwaites | | | Vonroemeria J. J. Sm. | Octarrhena Thwaites | Orchidaceae |
| Vrydagzynea Blume | | a | | Vrydagzynea Blume | | Orchidaceae |
| Wailesia Lindl. | Dipodium R. Br. | | | Wailesia Lindl. | Dipodium R. Br. | Orchidaceae |
| Waireia D. L. Jones et al. | | a | | Waireia D. L. Jones et al. | | Orchidaceae |
| Wallnoeferia Szlach. | Helonoma Garay | | | Wallnoeferia Szlach. | Helonoma Garay | Orchidaceae |
| Waluewa Regel | Gomesa R. Br. | | | Waluewa Regel | Gomesa R. Br. | Orchidaceae |
| ×Warczatoria J. M. H. Shaw | | a | | Warczatoria J. M. H. Shaw | | Orchidaceae |
| Warczewiczella Rchb. f. | | a | | Warczewiczella Rchb. f. | | Orchidaceae |
| Warmingia Rchb. f. | | a | | Warmingia Rchb. f. | | Orchidaceae |
| Warrea Lindl. | | a | | Warrea Lindl. | | Orchidaceae |
| Warreella Schltr. | | a | | Warreella Schltr. | | Orchidaceae |
| Warreopsis Garay | | a | | Warreopsis Garay | | Orchidaceae |
| Warscaea Szlach. | Cyclopogon C. Presl | | | Warscaea Szlach. | Cyclopogon C. Presl | Orchidaceae |
| Warscewiczella Rchb. f., orth. var. | Warczewiczella Rchb. f. | | | Warscewiczella Rchb. f., orth. var. | Warczewiczella Rchb. f. | Orchidaceae |
| ×Wilsonara hort. | | a | | Wilsonara hort. | | Orchidaceae |
| Winika M. A. Clem. et al. | Dendrobium Sw. | | | Winika M. A. Clem. et al. | Dendrobium Sw. | Orchidaceae |
| Wullschlaegelia Rchb. f. | | a | | Wullschlaegelia Rchb. f. | | Orchidaceae |
| Xaritonia Raf. | Tolumnia Raf. | | | Xaritonia Raf. | Tolumnia Raf. | Orchidaceae |
| Xeilyathum Raf. | Oncidium Sw. | | | Xeilyathum Raf. | Oncidium Sw. | Orchidaceae |
| Xenikophyton Garay | | a | | Xenikophyton Garay | | Orchidaceae |
| Xerorchis Schltr. | | a | | Xerorchis Schltr. | | Orchidaceae |
| Xiphizusa Rchb. f. | Bulbophyllum Thouars | | | Xiphizusa Rchb. f. | Bulbophyllum Thouars | Orchidaceae |
| Xiphophyllum Ehrh. | Cephalanthera Rich. | | | Xiphophyllum Ehrh. | Cephalanthera Rich. | Orchidaceae |
| Xiphosium Griff. | Eria Lindl. | | | Xiphosium Griff. | Eria Lindl. | Orchidaceae |
| Xylobium Lindl. | | a | | Xylobium Lindl. | | Orchidaceae |
| Yoania Maxim. | | a | | Yoania Maxim. | | Orchidaceae |
| Yolanda Hoehne | Brachionidium Lindl. | | | Yolanda Hoehne | Brachionidium Lindl. | Orchidaceae |
| Ypsilopus Summerh. | | a | | Ypsilopus Summerh. | | Orchidaceae |
| Zelenkoa M. W. Chase & N. H. Williams | | a | | Zelenkoa M. W. Chase & N. H. Williams | | Orchidaceae |
| ×Zelenkocidium J. M. H. Shaw | | a | | Zelenkocidium J. M. H. Shaw | | Orchidaceae |
| ×Zelglossoda J. M. H. Shaw | | a | | Zelglossoda J. M. H. Shaw | | Orchidaceae |
| Zetagyne Ridl. | Panisea (Lindl.) Lindl. | | | Zetagyne Ridl. | Panisea (Lindl.) Lindl. | Orchidaceae |
| Zeuxine Lindl. | | a | | Zeuxine Lindl. | | Orchidaceae |
| Zeuxinella Aver. | | a | | Zeuxinella Aver. | | Orchidaceae |
| Zhukowskia Szlach. et al. | | a | | Zhukowskia Szlach. et al. | | Orchidaceae |
| Zoophora Bernh. | Orchis L. | | | Zoophora Bernh. | Orchis L. | Orchidaceae |
| Zootrophion Luer | | a | | Zootrophion Luer | | Orchidaceae |
| Zosterophyllanthos Szlach. & Marg. | | a | | Zosterophyllanthos Szlach. & Marg. | | Orchidaceae |
| Zosterostylis Blume | Cryptostylis R. Br. | | | Zosterostylis Blume | Cryptostylis R. Br. | Orchidaceae |
| Zygoglossum Reinw. | Bulbophyllum Thouars | | | Zygoglossum Reinw. | Bulbophyllum Thouars | Orchidaceae |
| ×Zygonisia hort. | | a | | Zygonisia hort. | | Orchidaceae |
| Zygopetalon Hook., orth. var. | Zygopetalum Hook. | | | Zygopetalon Hook., orth. var. | Zygopetalum Hook. | Orchidaceae |
| Zygopetalum Hook. | | a | | Zygopetalum Hook. | | Orchidaceae |
| Zygosepalum Rchb. f. | | a | | Zygosepalum Rchb. f. | | Orchidaceae |
| Zygostates Lindl. | | a | | Zygostates Lindl. | | Orchidaceae |