| Lactuca alpina (L.) A. Gray | Cicerbita alpina (L.) Wallr. | | | Lactuca alpina (L.) A. Gray | Cicerbita alpina (L.) Wallr. | 21324 | 104152 |
| Lactuca altaica Fisch. & C. A. Mey. | | a | | Lactuca altaica Fisch. & C. A. Mey. | | 21325 | |
| Lactuca augustana All. | Lactuca serriola L. | | | Lactuca augustana All. | Lactuca serriola L. | 21326 | 21365 |
| Lactuca bourgaei (Boiss.) Irish & N. Taylor | Cicerbita bourgaei (Boiss.) Beauverd | | | Lactuca bourgaei (Boiss.) Irish & N. Taylor | Cicerbita bourgaei (Boiss.) Beauverd | 21327 | 104153 |
| Lactuca bracteata Hook. f. & Thomson ex C. B. Clarke | Melanoseris bracteata (Hook. f. & Thomson ex C. B. Clarke) N. Kilian | | | Lactuca bracteata Hook. f. & Thomson ex C. B. Clarke | Melanoseris bracteata (Hook. f. & Thomson ex C. B. Clarke) N. Kilian | 21328 | 468490 |
| Lactuca canadensis L. | | a | | Lactuca canadensis L. | | 21329 | |
| Lactuca canadensis L. var. longifolia (Michx.) Farw. | Lactuca canadensis L. | | i | Lactuca canadensis L. var.longifolia (Michx.) Farw. | Lactuca canadensis L. | 21330 | 21329 |
| Lactuca chinensis (Thunb.) Makino | Ixeris chinensis (Thunb.) Nakai | | | Lactuca chinensis (Thunb.) Makino | Ixeris chinensis (Thunb.) Nakai | 21331 | 104371 |
| Lactuca chondrilliflora Boreau | Lactuca viminea (L.) J. Presl & C. Presl subsp. chondrilliflora (Boreau) St.-Lag. | | | Lactuca chondrilliflora Boreau | Lactuca viminea (L.) J. Presl & C. Presl subsp. chondrilliflora (Boreau) St.-Lag. | 21332 | 104387 |
| Lactuca dentata (Thunb.) C. B. Rob. | Ixeridium dentatum (Thunb.) Tzvelev | | | Lactuca dentata (Thunb.) C. B. Rob. | Ixeridium dentatum (Thunb.) Tzvelev | 21333 | 411136 |
| Lactuca denticulata (Houtt.) Maxim. | Crepidiastrum denticulatum (Houtt.) Pak & Kawano | | | Lactuca denticulata (Houtt.) Maxim. | Crepidiastrum denticulatum (Houtt.) Pak & Kawano | 21334 | 463594 |
| Lactuca dissecta D. Don | | a | | Lactuca dissecta D. Don | | 21335 | |
| Lactuca dregeana DC. | | a | | Lactuca dregeana DC. | | 21336 | |
| Lactuca dubyaea C. B. Clarke | Dubyaea hispida DC. | | | Lactuca dubyaea C. B. Clarke | Dubyaea hispida DC. | 21337 | 104197 |
| Lactuca graciliflora DC. | Melanoseris graciliflora (DC.) N. Kilian | | | Lactuca graciliflora DC. | Melanoseris graciliflora (DC.) N. Kilian | 21338 | 468494 |
| Lactuca hastata DC. | Melanoseris cyanea (D. Don) Edgew. | | | Lactuca hastata DC. | Melanoseris cyanea (D. Don) Edgew. | 21339 | 468491 |
| Lactuca hirsuta Muhl. ex Nutt. var. sanguinea (Bigelow) Fernald | Lactuca hirsuta Muhl. ex Nutt. | | i | Lactuca hirsuta Muhl. ex Nutt. var.sanguinea (Bigelow) Fernald | Lactuca hirsuta Muhl. ex Nutt. | 21340 | 104382 |
| Lactuca indica L. | | a | | Lactuca indica L. | | 21341 | |
| Lactuca keiskeana (Maxim.) Makino | Crepidiastrum keiskeanum (Maxim.) Nakai | | | Lactuca keiskeana (Maxim.) Makino | Crepidiastrum keiskeanum (Maxim.) Nakai | 21342 | 411137 |
| Lactuca lessertiana (DC.) C. B. Clarke | | a | | Lactuca lessertiana (DC.) C. B. Clarke | | 21343 | |
| Lactuca livida Boiss. & Reut. | Lactuca virosa L. subsp. livida (Boiss. & Reut.) Ladero & A. Velasco | | | Lactuca livida Boiss. & Reut. | Lactuca virosa L. subsp. livida (Boiss. & Reut.) Ladero & A. Velasco | 21344 | 458702 |
| Lactuca longifolia DC. | Lactuca dolichophylla Kitam. | | | Lactuca longifolia DC. | Lactuca dolichophylla Kitam. | 21345 | 104381 |
| Lactuca longifolia Michx. | Lactuca canadensis L. | | | Lactuca longifolia Michx. | Lactuca canadensis L. | 21346 | 21329 |
| Lactuca macrantha C. B. Clarke | Melanoseris macrantha (C. B. Clarke) N. Kilian & J. W. Zhang | | | Lactuca macrantha C. B. Clarke | Melanoseris macrantha (C. B. Clarke) N. Kilian & J. W. Zhang | 21347 | 468493 |
| Lactuca macrophylla (Willd.) A. Gray | Cicerbita macrophylla (Willd.) Wallr. | | | Lactuca macrophylla (Willd.) A. Gray | Cicerbita macrophylla (Willd.) Wallr. | 21348 | 104383 |
| Lactuca macrorrhiza (Royle) Hook. f. | Melanoseris macrorrhiza (Royle) N. Kilian | | | Lactuca macrorrhiza (Royle) Hook. f. | Melanoseris macrorrhiza (Royle) N. Kilian | 21349 | 468492 |
| Lactuca muralis (L.) Gaertn., nom. inval. | Cicerbita muralis (L.) Wallr. | | | Lactuca muralis (L.) Gaertn., nom. inval. | Cicerbita muralis (L.) Wallr. | 21350 | 463125 |
| Lactuca orientalis (Boiss.) Boiss. | | a | | Lactuca orientalis (Boiss.) Boiss. | | 21351 | |
| Lactuca perennis L. | | a | | Lactuca perennis L. | | 21352 | |
| Lactuca plumieri (L.) Gren. & Godr. | Cicerbita plumieri (L.) Kirschl. | | | Lactuca plumieri (L.) Gren. & Godr. | Cicerbita plumieri (L.) Kirschl. | 21353 | 104157 |
| Lactuca polycephala (Cass.) C. B. Clarke | Ixeris polycephala Cass. | | | Lactuca polycephala (Cass.) C. B. Clarke | Ixeris polycephala Cass. | 21354 | 20539 |
| Lactuca pulchella (Pursh) DC. | Lactuca tatarica (L.) C. A. Mey. subsp. pulchella (Pursh) Stebbins | | | Lactuca pulchella (Pursh) DC. | Lactuca tatarica (L.) C. A. Mey. subsp. pulchella (Pursh) Stebbins | 21355 | 104386 |
| Lactuca quercina L. | | a | | Lactuca quercina L. | | 21356 | |
| Lactuca raddeana Maxim. | | a | | Lactuca raddeana Maxim. | | 21357 | |
| Lactuca sagittata Waldst. & Kit. | Lactuca quercina L. | | | Lactuca sagittata Waldst. & Kit. | Lactuca quercina L. | 21358 | 21356 |
| Lactuca saligna L. | | a | | Lactuca saligna L. | | 21359 | |
| Lactuca sativa L. | | a | | Lactuca sativa L. | | 21360 | |
| Lactuca sativa L. var. capitata L. | | a | i | Lactuca sativa L. var.capitata L. | | 21361 | |
| Lactuca sativa L. var. longifolia Lam. | | a | i | Lactuca sativa L. var.longifolia Lam. | | 21362 | |
| Lactuca sativa L. var. romana L. H. Bailey | Lactuca sativa L. var. longifolia Lam. | | i | Lactuca sativa L. var.romana L. H. Bailey | Lactuca sativa L. var.longifolia Lam. | 21363 | 21362 |
| Lactuca scariola L. | Lactuca serriola L. | | | Lactuca scariola L. | Lactuca serriola L. | 21364 | 21365 |
| Lactuca serriola L. | | a | | Lactuca serriola L. | | 21365 | |
| Lactuca sibirica (L.) Benth. ex Maxim. | | a | | Lactuca sibirica (L.) Benth. ex Maxim. | | 21366 | |
| Lactuca sonchifolia Willd. | Lactuca tuberosa Jacq. | | | Lactuca sonchifolia Willd. | Lactuca tuberosa Jacq. | 21367 | 21372 |
| Lactuca spicata (Lam.) Hitchc. | Cicerbita alpina (L.) Wallr. | | | Lactuca spicata (Lam.) Hitchc. | Cicerbita alpina (L.) Wallr. | 21368 | 104152 |
| Lactuca squarrosa (Thunb.) Miq. | Lactuca indica L. | | | Lactuca squarrosa (Thunb.) Miq. | Lactuca indica L. | 21369 | 21341 |
| Lactuca tatarica (L.) C. A. Mey. | | a | | Lactuca tatarica (L.) C. A. Mey. | | 21370 | |
| Lactuca tenerrima Pourr. | | a | | Lactuca tenerrima Pourr. | | 21371 | |
| Lactuca tuberosa Jacq. | | a | | Lactuca tuberosa Jacq. | | 21372 | |
| Lactuca undulata Ledeb. | | a | | Lactuca undulata Ledeb. | | 21373 | |
| Lactuca viminea (L.) J. Presl & C. Presl | | a | | Lactuca viminea (L.) J. Presl & C. Presl | | 21374 | |
| Lactuca virosa L. | | a | | Lactuca virosa L. | | 21375 | |
| Lactuca biennis (Moench) Fernald | | a | | Lactuca biennis (Moench) Fernald | | 104379 | |
| Lactuca dolichophylla Kitam. | | a | | Lactuca dolichophylla Kitam. | | 104381 | |
| Lactuca hirsuta Muhl. ex Nutt. | | a | | Lactuca hirsuta Muhl. ex Nutt. | | 104382 | |
| Lactuca scarioloides Boiss. | | a | | Lactuca scarioloides Boiss. | | 104384 | |
| Lactuca tatarica (L.) C. A. Mey. subsp. pulchella (Pursh) Stebbins | | a | i | Lactuca tatarica (L.) C. A. Mey. subsp. pulchella (Pursh) Stebbins | | 104386 | |
| Lactuca viminea (L.) J. Presl & C. Presl subsp. chondrilliflora (Boreau) St.-Lag. | | a | i | Lactuca viminea (L.) J. Presl & C. Presl subsp. chondrilliflora (Boreau) St.-Lag. | | 104387 | |
| Lactuca spp. | | a | | Lactuca spp. | | 300295 | |
| Lactuca serriola L. f. integrifolia (Gray) S. D. Prince & R. N. Carter | | a | i | Lactuca serriola L. f. integrifolia (Gray) S. D. Prince & R. N. Carter | | 313984 | |
| Lactuca virosa L. var. integrifolia Gray | Lactuca serriola L. f. integrifolia (Gray) S. D. Prince & R. N. Carter | | i | Lactuca virosa L. var.integrifolia Gray | Lactuca serriola L. f. integrifolia (Gray) S. D. Prince & R. N. Carter | 313985 | 313984 |
| Lactuca tatarica (L.) C. A. Mey. subsp. tatarica | | a | i | Lactuca tatarica (L.) C. A. Mey. subsp. tatarica | | 317707 | |
| Lactuca oblongifolia Nutt. | Lactuca tatarica (L.) C. A. Mey. subsp. pulchella (Pursh) Stebbins | | | Lactuca oblongifolia Nutt. | Lactuca tatarica (L.) C. A. Mey. subsp. pulchella (Pursh) Stebbins | 400596 | 104386 |
| Lactuca sativa L. var. crispa L. | | a | i | Lactuca sativa L. var.crispa L. | | 404618 | |
| Lactuca sativa L. var. angustana Irish | | a | i | Lactuca sativa L. var.angustana Irish | | 404620 | |
| Lactuca viminea (L.) J. Presl & C. Presl subsp. viminea | | a | i | Lactuca viminea (L.) J. Presl & C. Presl subsp. viminea | | 434183 | |
| Lactuca capensis Thunb. | Lactuca inermis Forssk. | | | Lactuca capensis Thunb. | Lactuca inermis Forssk. | 450176 | 450971 |
| Lactuca inermis Forssk. | | a | | Lactuca inermis Forssk. | | 450971 | |
| Lactuca floridana (L.) Gaertn. | | a | | Lactuca floridana (L.) Gaertn. | | 451254 | |
| Lactuca canadensis L. var. latifolia Kuntze | Lactuca canadensis L. | | i | Lactuca canadensis L. var.latifolia Kuntze | Lactuca canadensis L. | 451975 | 21329 |
| Lactuca georgica Grossh. | | a | | Lactuca georgica Grossh. | | 454236 | |
| Lactuca azerbaijanica Rech. f. | | a | | Lactuca azerbaijanica Rech. f. | | 454237 | |
| Lactuca aculeata Boiss. & Kotschy | | a | | Lactuca aculeata Boiss. & Kotschy | | 454238 | |
| Lactuca marschallii Stebbins | Cicerbita prenanthoides (M. Bieb.) Beauverd | | | Lactuca marschallii Stebbins | Cicerbita prenanthoides (M. Bieb.) Beauverd | 454245 | 454243 |
| Lactuca acanthifolia (Willd.) Boiss. | | a | | Lactuca acanthifolia (Willd.) Boiss. | | 458682 | |
| Lactuca longidentata Moris ex DC. | | a | | Lactuca longidentata Moris ex DC. | | 458684 | |
| Lactuca viminea (L.) J. Presl & C. Presl subsp. ramosissima (All.) Arcang. | | a | i | Lactuca viminea (L.) J. Presl & C. Presl subsp. ramosissima (All.) Arcang. | | 458685 | |
| Lactuca alpestris (Gand.) Rech. f. | | a | | Lactuca alpestris (Gand.) Rech. f. | | 458687 | |
| Lactuca viminea (L.) J. Presl & C. Presl subsp. alpestris (Gand.) Feráková | Lactuca alpestris (Gand.) Rech. f. | | i | Lactuca viminea (L.) J. Presl & C. Presl subsp. alpestris (Gand.) Feráková | Lactuca alpestris (Gand.) Rech. f. | 458689 | 458687 |
| Lactuca watsoniana Trel. | | a | | Lactuca watsoniana Trel. | | 458690 | |
| Lactuca aurea (Vis. & Pančić) Stebbins | | a | | Lactuca aurea (Vis. & Pančić) Stebbins | | 458691 | |
| Lactuca intricata Boiss. | | a | | Lactuca intricata Boiss. | | 458693 | |
| Lactuca graeca Boiss. | Lactuca intricata Boiss. | | | Lactuca graeca Boiss. | Lactuca intricata Boiss. | 458694 | 458693 |
| Lactuca intybacea Jacq. | Launaea intybacea (Jacq.) Beauverd | | | Lactuca intybacea Jacq. | Launaea intybacea (Jacq.) Beauverd | 458696 | 458710 |
| Lactuca ludoviciana (Nutt.) Riddell | | a | | Lactuca ludoviciana (Nutt.) Riddell | | 458697 | |
| Lactuca graminifolia Michx. | | a | | Lactuca graminifolia Michx. | | 458699 | |
| Lactuca jamaicensis Griseb. | | a | | Lactuca jamaicensis Griseb. | | 458700 | |
| Lactuca auriculata DC. | Lactuca dissecta D. Don | | | Lactuca auriculata DC. | Lactuca dissecta D. Don | 458701 | 21335 |
| Lactuca virosa L. subsp. livida (Boiss. & Reut.) Ladero & A. Velasco | | a | i | Lactuca virosa L. subsp. livida (Boiss. & Reut.) Ladero & A. Velasco | | 458702 | |
| Lactuca virosa L. subsp. cornigera (Pau & Font Quer) Emb. & Maire | | a | i | Lactuca virosa L. subsp. cornigera (Pau & Font Quer) Emb. & Maire | | 458703 | |
| Lactuca virosa L. subsp. virosa | | a | i | Lactuca virosa L. subsp. virosa | | 458704 | |
| Lactuca cornigera Pau & Font Quer | Lactuca virosa L. subsp. cornigera (Pau & Font Quer) Emb. & Maire | | | Lactuca cornigera Pau & Font Quer | Lactuca virosa L. subsp. cornigera (Pau & Font Quer) Emb. & Maire | 458705 | 458703 |
| Lactuca quercina L. subsp. quercina | | a | i | Lactuca quercina L. subsp. quercina | | 458706 | |
| Lactuca quercina L. subsp. wilhemsiana (Fisch. & C. A. Mey. ex DC.) Feráková | | a | i | Lactuca quercina L. subsp. wilhemsiana (Fisch. & C. A. Mey. ex DC.) Feráková | | 458707 | |
| Lactuca wilhemsiana Fisch. & C. A. Mey. ex DC. | Lactuca quercina L. subsp. wilhemsiana (Fisch. & C. A. Mey. ex DC.) Feráková | | | Lactuca wilhemsiana Fisch. & C. A. Mey. ex DC. | Lactuca quercina L. subsp. wilhemsiana (Fisch. & C. A. Mey. ex DC.) Feráková | 458708 | 458707 |
| Lactuca hybr. | | a | | Lactuca hybr. | | 458711 | |
| Lactuca chaixii Vill. | Lactuca quercina L. subsp. quercina | | | Lactuca chaixii Vill. | Lactuca quercina L. subsp. quercina | 461044 | 458706 |
| Lactuca sativa L. subsp. capitata (L.) Schübl. & G. Martens | Lactuca sativa L. var. capitata L. | | i | Lactuca sativa L. subsp. capitata (L.) Schübl. & G. Martens | Lactuca sativa L. var.capitata L. | 464070 | 21361 |
| Lactuca sativa L. subsp. crispa (L.) Schübl. & G. Martens | Lactuca sativa L. var. crispa L. | | i | Lactuca sativa L. subsp. crispa (L.) Schübl. & G. Martens | Lactuca sativa L. var.crispa L. | 464071 | 404618 |
| Lactuca spinidens Nevski | | a | | Lactuca spinidens Nevski | | 464409 | |
| Lactuca rosularis Boiss. | | a | | Lactuca rosularis Boiss. | | 464410 | |
| Lactuca glaucifolia Boiss. | | a | | Lactuca glaucifolia Boiss. | | 464411 | |
| Lactuca winkleri Kirp. | | a | | Lactuca winkleri Kirp. | | 464412 | |
| Lactuca stricta Waldst. & Kit. | Lactuca quercina L. subsp. quercina | | | Lactuca stricta Waldst. & Kit. | Lactuca quercina L. subsp. quercina | 464414 | 458706 |
| Lactuca triangulata Maxim. | | a | | Lactuca triangulata Maxim. | | 464415 | |
| Lactuca alaica Kovalevsk. | | a | | Lactuca alaica Kovalevsk. | | 464417 | |
| Lactuca petitiana A. Rich. | Launaea petitiana (A. Rich.) N. Kilian | | | Lactuca petitiana A. Rich. | Launaea petitiana (A. Rich.) N. Kilian | 464688 | 464687 |
| Lactuca taraxacifolia (Willd.) Schumach. | Launaea taraxacifolia (Willd.) Amin ex C. Jeffrey | | | Lactuca taraxacifolia (Willd.) Schumach. | Launaea taraxacifolia (Willd.) Amin ex C. Jeffrey | 465518 | 464689 |
| Lactuca sativa L. var. secalina (Alef.) Juckenack | Lactuca sativa L. var. crispa L. | | i | Lactuca sativa L. var.secalina (Alef.) Juckenack | Lactuca sativa L. var.crispa L. | 468511 | 404618 |
| Lactuca sativa L. var.-gr. secalina Alef. | Lactuca sativa L. var. crispa L. | | i | Lactuca sativa L. var.-gr. secalina Alef. | Lactuca sativa L. var.crispa L. | 468512 | 404618 |
| Lactuca homblei De Wild. | | a | | Lactuca homblei De Wild. | | 468951 | |
| Lactuca singularis Wilmott | | a | | Lactuca singularis Wilmott | | 474773 | |
| Lactuca squarrosa (Thunb.) Miq. var. laciniata Kuntze | Lactuca indica L. | | i | Lactuca squarrosa (Thunb.) Miq. var.laciniata Kuntze | Lactuca indica L. | 480678 | 21341 |
| Lactuca indica L. var. laciniata (Kuntze) H. Hara | Lactuca indica L. | | i | Lactuca indica L. var.laciniata (Kuntze) H. Hara | Lactuca indica L. | 480679 | 21341 |
| Lactuca indica L. var. indica | Lactuca indica L. | | i | Lactuca indica L. var.indica | Lactuca indica L. | 480694 | 21341 |
| Lactuca canadensis L. var. canadensis | Lactuca canadensis L. | | i | Lactuca canadensis L. var.canadensis | Lactuca canadensis L. | 482674 | 21329 |
| Lactuca hirsuta Muhl. ex Nutt. var. hirsuta | Lactuca hirsuta Muhl. ex Nutt. | | i | Lactuca hirsuta Muhl. ex Nutt. var.hirsuta | Lactuca hirsuta Muhl. ex Nutt. | 482675 | 104382 |
| Lactuca sativa L. subsp. sativa | Lactuca sativa L. var. sativa | | i | Lactuca sativa L. subsp. sativa | Lactuca sativa L. var.sativa | 482676 | 482677 |
| Lactuca sativa L. var. sativa | | a | i | Lactuca sativa L. var.sativa | | 482677 | |
| Lactuca serriola L. f. serriola | | a | i | Lactuca serriola L. f. serriola | | 482678 | |
| Lactuca virosa L. var. virosa | Lactuca virosa L. subsp. virosa | | i | Lactuca virosa L. var.virosa | Lactuca virosa L. subsp. virosa | 482679 | 458704 |
| Lactuca angustana Hort. ex Vilm., nom. inval. | Lactuca sativa L. var. angustana Irish | | | Lactuca angustana Hort. ex Vilm., nom. inval. | Lactuca sativa L. var.angustana Irish | 485451 | 404620 |
| Lactuca sativa L. var. asparagina L. H. Bailey | Lactuca sativa L. var. angustana Irish | | i | Lactuca sativa L. var.asparagina L. H. Bailey | Lactuca sativa L. var.angustana Irish | 485455 | 404620 |