| Symbol | Scientific name | Common name/Accepted name (for synonyms) | Family |
| YUKA2 | Yucca kanabensis McKelvey | Yucca angustissima var. kanabensis | Agavaceae
|
| YUKA3 | Yucca �karlsruhensis Graebn. | | Agavaceae
|
| YULO | Yucca louisianensis Trel. | Gulf Coast yucca | Agavaceae
|
| YUMA2 | Yucca macrocarpa (Torr.) Coville | Yucca torreyi | Agavaceae
|
| YUMA3 | Yucca macrocarpa Engelm., non Merriam | Yucca schottii | Agavaceae
|
| YUMA | Yucca macrocarpa Merriam, non Engelm. | Yucca schidigera | Agavaceae
|
| YUMO2 | Yucca mohavensis Sarg. | Yucca schidigera | Agavaceae
|
| YUNA | Yucca navajoa J.M. Webber | Yucca baileyi var. navajoa | Agavaceae
|
| YUNE | Yucca necopina Shinners | Brazos River yucca | Agavaceae
|
| YUNE4 | Yucca neomexicana Woot. & Standl. | Yucca harrimaniae var. neomexicana | Agavaceae
|
| YUNE3 | Yucca newberryi McKelvey | Yucca whipplei var. whipplei | Agavaceae
|
| YUNI | Yucca nitida C. Wright ex W. Wats. | Yucca whipplei var. whipplei | Agavaceae
|
| YUPA | Yucca pallida McKelvey | twistleaf yucca | Agavaceae
|
| YUPU | Yucca puberula Torr. | Yucca schottii | Agavaceae
|
| YURE2 | Yucca recurvifolia Salisb. | Yucca filamentosa | Agavaceae
|
| YURE | Yucca reverchonii Trel. | San Angelo yucca | Agavaceae
|
| YUROL | Yucca rostrata Engelm. ex Trel. var. linearis Trel. | Yucca thompsoniana | Agavaceae
|
| YURO | Yucca rostrata Engelm. ex Trel. | Yucca thompsoniana | Agavaceae
|
| YURU | Yucca rupicola Scheele | Texas yucca | Agavaceae
|
| YURU2 | Yucca rupicola Trel. | Yucca pallida | Agavaceae
|
| YUSC2 | Yucca schidigera Roezl ex Ortgies | Mojave yucca | Agavaceae
|
| YUSC | Yucca schottii Engelm. | Schott's yucca | Agavaceae
|
| YUSM | Yucca smalliana Fern. | Yucca filamentosa | Agavaceae
|
| YUST2 | Yucca standleyi McKelvey | Yucca baileyi var. baileyi | Agavaceae
|
| YUTE | Yucca tenuistyla Trel. | whiterim yucca | Agavaceae
|
| YUTH | Yucca thompsoniana Trel. | Thompson's yucca | Agavaceae
|
| YUTH2 | Yucca thornberi McKelvey | Yucca baccata var. brevifolia | Agavaceae
|
| YUTO2 | Yucca toftiae Welsh | Yucca angustissima var. toftiae | Agavaceae
|
| YUTO | Yucca torreyi Shafer | Torrey's yucca | Agavaceae
|
| YUTO3 | Yucca tortifolia Lindl. ex Engelm. | Yucca rupicola | Agavaceae
|
| YUTRC | Yucca treculeana Carr. var. canaliculata Trel. | Yucca treculeana var. treculeana | Agavaceae
|
| YUTRS | Yucca treculeana Carr. var. succulenta McKelvey | Don Quixote's lace | Agavaceae
|
| YUTRT | Yucca treculeana Carr. var. treculeana | Don Quixote's lace | Agavaceae
|
| YUTR | Yucca treculeana Carr. | Don Quixote's lace | Agavaceae
|
| YUTR2 | Yucca treleasei J.F. Macbr. | Yucca baccata var. brevifolia | Agavaceae
|
| YUUT2 | Yucca utahensis McKelvey | Yucca elata var. utahensis | Agavaceae
|
| YUVE | Yucca verdiensis McKelvey | Yucca elata var. verdiensis | Agavaceae
|
| YUVE2 | Yucca vespertina (McKelvey) Welsh | Yucca baccata var. vespertina | Agavaceae
|
| YUWHC | Yucca whipplei Torr. ssp. caespitosa (M.E. Jones) Haines | Yucca whipplei var. caespitosa | Agavaceae
|
| YUWHI | Yucca whipplei Torr. ssp. intermedia Haines | Yucca whipplei var. whipplei | Agavaceae
|
| YUWHP | Yucca whipplei Torr. ssp. parishii (M.E. Jones) Haines | Yucca whipplei var. whipplei | Agavaceae
|
| YUWHP2 | Yucca whipplei Torr. ssp. percursa Haines | Yucca whipplei var. whipplei | Agavaceae
|
| YUWHC2 | Yucca whipplei Torr. var. caespitosa M.E. Jones | chaparral yucca | Agavaceae
|
| YUWHG | Yucca whipplei Torr. var. graminifolia (Wood) Trel. | Yucca whipplei var. whipplei | Agavaceae
|
| YUWHI2 | Yucca whipplei Torr. var. intermedia (Haines) J.M. Webber | Yucca whipplei var. whipplei | Agavaceae
|
| YUWHP3 | Yucca whipplei Torr. var. parishii M.E. Jones | Yucca whipplei var. whipplei | Agavaceae
|
| YUWHP4 | Yucca whipplei Torr. var. percursa (Haines) J.M. Webber | Yucca whipplei var. whipplei | Agavaceae
|
| YUWHW | Yucca whipplei Torr. var. whipplei | chaparral yucca | Agavaceae
|
| YUWH | Yucca whipplei Torr. | chaparral yucca | Agavaceae
|
| YUCCA | Yucca L. | yucca | Agavaceae
|
| ZACA7 | Zahlbrucknerella calcarea (Herre) Herre | | Lichinaceae
|
| ZACA8 | Zahlbrucknerella californica Henssen | | Lichinaceae
|
| ZAFA2 | Zahlbrucknerella fabispora Henssen | | Lichinaceae
|
| ZAHLB | Zahlbrucknerella Herre | zahlbrucknerella | Lichinaceae
|
| ZAGR | Zaluzania grayana Robins. & Greenm. | Viguiera triloba | Asteraceae
|
| ZAAN2 | Zamia angustifolia Jacq. | Zamia pumila | Zamiaceae
|
| ZADE | Zamia debilis Ait. | Zamia pumila | Zamiaceae
|
| ZAFL2 | Zamia floridana A. DC. | Zamia pumila | Zamiaceae
|
| ZAIN | Zamia integrifolia Ait. | Zamia pumila | Zamiaceae
|
| ZALA | Zamia latifoliolata Preneloup | Zamia pumila | Zamiaceae
|
| ZAME | Zamia media Jacq. | Zamia pumila | Zamiaceae
|
| ZAPO | Zamia portoricensis Urban | Zamia pumila | Zamiaceae
|
| ZAPU | Zamia pumila L. | coontie | Zamiaceae
|
| ZASI | Zamia silvicola Small | Zamia pumila | Zamiaceae
|
| ZAUM | Zamia umbrosa Small | Zamia pumila | Zamiaceae
|
| ZAMIA | Zamia L. | zamia | Zamiaceae
|
| ZARU | Zamzela rugosa (Thuill. ex Pers.) Raf. | Hirtella rugosa | Chrysobalanaceae
|
| ZAMA4 | Zannichellia major (Hartman) Boenn. ex Reichenb. | Zannichellia palustris | Zannichelliaceae
|
| ZAPAM | Zannichellia palustris L. var. major (Hartman) W.D.J. Koch | Zannichellia palustris | Zannichelliaceae
|
| ZAPAS | Zannichellia palustris L. var. stenophylla Aschers. & Graebn. | Zannichellia palustris | Zannichelliaceae
|
| ZAPA | Zannichellia palustris L. | horned pondweed | Zannichelliaceae
|
| ZANNI | Zannichellia L. | horned pondweed | Zannichelliaceae
|
| ZAAE | Zantedeschia aethiopica (L.) Spreng. | calla lily | Araceae
|
| ZAAL | Zantedeschia albomaculata (Hook.) Baill. | spotted calla lily | Araceae
|
| ZANTE | Zantedeschia Spreng. | calla lily | Araceae
|
| ZAAM | Zanthoxylum americanum P. Mill. | common pricklyash | Rutaceae
|
| ZABI | Zanthoxylum bifoliolatum L�onard | Maricao pricklyash | Rutaceae
|
| ZABL | Zanthoxylum bluettianum Rock | Zanthoxylum hawaiiense | Rutaceae
|
| ZACA3 | Zanthoxylum caribaeum Lam. | prickly yellow | Rutaceae
|
| ZACLF2 | Zanthoxylum clava-herculis L. var. fruticosum (Gray) S. Wats. | Zanthoxylum hirsutum | Rutaceae
|
| ZACL | Zanthoxylum clava-herculis L. | Hercules' club | Rutaceae
|
| ZACO | Zanthoxylum coriaceum A. Rich. | Biscayne pricklyash | Rutaceae
|
| ZADID | Zanthoxylum dipetalum Mann var. degeneri (Skottsberg) St. John | Zanthoxylum dipetalum var. dipetalum | Rutaceae
|
| ZADID2 | Zanthoxylum dipetalum Mann var. dipetalum | kawa'u | Rutaceae
|
| ZADIG | Zanthoxylum dipetalum Mann var. geminicarpum Rock | Zanthoxylum dipetalum var. dipetalum | Rutaceae
|
| ZADIH | Zanthoxylum dipetalum Mann var. hillebrandii (Sherff) St. John | Zanthoxylum dipetalum var. dipetalum | Rutaceae
|
| ZADIM | Zanthoxylum dipetalum Mann var. mannii (Sherff) St. John | Zanthoxylum dipetalum var. dipetalum | Rutaceae
|
| ZADIT | Zanthoxylum dipetalum Mann var. tomentosum Rock | kawa'u | Rutaceae
|
| ZADI | Zanthoxylum dipetalum Mann | kawa'u | Rutaceae
|
| ZAFA | Zanthoxylum fagara (L.) Sarg. | lime pricklyash | Rutaceae
|
| ZAFL | Zanthoxylum flavum Vahl | West Indian satinwood | Rutaceae
|
| ZAGL | Zanthoxylum glandulosum Hbd., non Raf. | Zanthoxylum kauaense | Rutaceae
|
| ZAHAC | Zanthoxylum hawaiiense Hbd. var. citriodorum Rock | Zanthoxylum hawaiiense | Rutaceae
|
| ZAHAS | Zanthoxylum hawaiiense Hbd. var. subacutum (Sherff) St. John | Zanthoxylum hawaiiense | Rutaceae
|
| ZAHAV | Zanthoxylum hawaiiense Hbd. var. velutinosum Rock | Zanthoxylum hawaiiense | Rutaceae
|
| ZAHA | Zanthoxylum hawaiiense Hbd. | Hawai'i pricklyash | Rutaceae
|
| ZAHIH | Zanthoxylum hillebrandii Waterman var. hiloense (Sherff) St. John | Zanthoxylum kauaense | Rutaceae
|
| ZAHI | Zanthoxylum hillebrandii Waterman | Zanthoxylum kauaense | Rutaceae
|
| ZAHI2 | Zanthoxylum hirsutum Buckl. | Texas Hercules' club | Rutaceae
|
| ZAKAK2 | Zanthoxylum kauaense Gray var. kohalanum (Sherff) St. John | Zanthoxylum kauaense | Rutaceae
|
| ZAKAK3 | Zanthoxylum kauaense Gray var. kohuanum (Skottsberg) St. John | Zanthoxylum kauaense | Rutaceae
|