| Symbol | Scientific name | Common name/Accepted name (for synonyms) | Family |
| ZAKA | Zanthoxylum kauaense Gray | Kauai pricklyash | Rutaceae
|
| ZAMA3 | Zanthoxylum macrophyllum Nutt. | Zanthoxylum clava-herculis | Rutaceae
|
| ZAMA | Zanthoxylum martinicense (Lam.) DC. | white pricklyash | Rutaceae
|
| ZAMAA | Zanthoxylum maviense Mann var. anceps Rock | Zanthoxylum kauaense | Rutaceae
|
| ZAMAC | Zanthoxylum maviense Mann var. cranwelliae (Skottsberg) St. John | Zanthoxylum kauaense | Rutaceae
|
| ZAMAK | Zanthoxylum maviense Mann var. kaalanum (Sherff) St. John | Zanthoxylum kauaense | Rutaceae
|
| ZAMAL | Zanthoxylum maviense Mann var. lanaiense (Sherff) St. John | Zanthoxylum kauaense | Rutaceae
|
| ZAMAM | Zanthoxylum maviense Mann var. maunahuiense (Sherff) St. John | Zanthoxylum kauaense | Rutaceae
|
| ZAMAR | Zanthoxylum maviense Mann var. rigidum Rock | Zanthoxylum kauaense | Rutaceae
|
| ZAMA2 | Zanthoxylum maviense Mann | Zanthoxylum kauaense | Rutaceae
|
| ZAMO2 | Zanthoxylum molokaiense B.C. Stone | Zanthoxylum kauaense | Rutaceae
|
| ZAMO | Zanthoxylum monophyllum (Lam.) P. Wilson | yellow prickle | Rutaceae
|
| ZAOA | Zanthoxylum oahuense Hbd. | Oahu pricklyash | Rutaceae
|
| ZAPA2 | Zanthoxylum parvum Shinners | tickletongue | Rutaceae
|
| ZAPU2 | Zanthoxylum punctatum Vahl | dotted pricklyash | Rutaceae
|
| ZASES | Zanthoxylum semiarticulatum St. John & Hosaka var. sessile (O. Deg.) Fosberg | Zanthoxylum kauaense | Rutaceae
|
| ZASE2 | Zanthoxylum semiarticulatum St. John & Hosaka | Zanthoxylum kauaense | Rutaceae
|
| ZASK | Zanthoxylum skottsbergii (O.& I. Deg.) St. John | Zanthoxylum kauaense | Rutaceae
|
| ZASP | Zanthoxylum spinifex (Jacq.) DC. | niaragato | Rutaceae
|
| ZATH | Zanthoxylum thomasianum (Krug & Urban) Krug & Urban ex P. Wilson | St. Thomas pricklyash | Rutaceae
|
| ZANTH | Zanthoxylum L. | pricklyash | Rutaceae
|
| ZAPO2 | Zapoteca portoricensis (Jacq.) H. Hern�ndez | white stickpea | Fabaceae
|
| ZAPOT | Zapoteca H. Hern�ndez | white stickpea | Fabaceae
|
| ZACAA2 | Zauschneria californica K. Presl ssp. angustifolia Keck | Epilobium canum ssp. angustifolium | Onagraceae
|
| ZACAL2 | Zauschneria californica K. Presl ssp. latifolia (Hook.) Keck | Epilobium canum ssp. latifolium | Onagraceae
|
| ZACAM | Zauschneria californica K. Presl ssp. mexicana (K. Presl) Raven | Epilobium canum ssp. canum | Onagraceae
|
| ZACAV | Zauschneria californica K. Presl var. villosa (Greene) Jepson | Epilobium canum ssp. canum | Onagraceae
|
| ZACA6 | Zauschneria californica K. Presl | Epilobium canum ssp. angustifolium | Onagraceae
|
| ZACA4 | Zauschneria cana Greene | Epilobium canum ssp. canum | Onagraceae
|
| ZAGA2 | Zauschneria garrettii A. Nels. | Epilobium canum ssp. garrettii | Onagraceae
|
| ZALAA | Zauschneria latifolia (Hook.) Greene var. arizonica (A. Davids.) Hilend | Epilobium canum ssp. latifolium | Onagraceae
|
| ZALAG | Zauschneria latifolia (Hook.) Greene var. garrettii (A. Nels.) Hilend | Epilobium canum ssp. garrettii | Onagraceae
|
| ZALA2 | Zauschneria latifolia (Hook.) Greene | Epilobium canum ssp. latifolium | Onagraceae
|
| ZASE3 | Zauschneria septentrionalis Keck | Epilobium septentrionale | Onagraceae
|
| ZEDI | Zea diploperennis Iltis, Doebley, & Guzman | diploperennial teosinte | Poaceae
|
| ZELU | Zea luxurians (Durieu & Asch.) Bird | teosinte | Poaceae
|
| ZEMAM2 | Zea mays L. ssp. mays | corn | Poaceae
|
| ZEMAM | Zea mays L. ssp. mexicana (Schrad.) Iltis | Zea mexicana | Poaceae
|
| ZEMAH | Zea mays L. ssp. parviglumis Iltis & Doebley var. huehuetenangensis Iltis & Doebley | maize | Poaceae
|
| ZEMAP | Zea mays L. ssp. parviglumis Iltis & Doebley | corn | Poaceae
|
| ZEMA | Zea mays L. | corn | Poaceae
|
| ZEME | Zea mexicana (Schrad.) Kuntze | Mexican teosinte | Poaceae
|
| ZEPE | Zea perennis (A.S. Hitchc.) Reeves & Manglesdorf | perennial teosinte | Poaceae
|
| ZEA | Zea L. | corn | Poaceae
|
| ZEPEQ | Zebrina pendula Schinz var. quadrifolia Bailey | Tradescantia zebrina | Commelinaceae
|
| ZEPE2 | Zebrina pendula Schinz | Tradescantia zebrina | Commelinaceae
|
| ZEBRI2 | Zebrina Schnizl. | zebrina | Commelinaceae
|
| ZESE80 | Zelkova serrata (Thunb.) Makino | Japanese zelkova | Ulmaceae
|
| ZELKO8 | Zelkova Spach | zelkova | Ulmaceae
|
| ZEPA | Zelometeorium patulum (Hedw.) Man. | zelometeorium moss | Meteoriaceae
|
| ZELOM | Zelometeorium Man. | zelometeorium moss | Meteoriaceae
|
| ZECA2 | Zenobia cassinefolia (Vent.) Pollard | Zenobia pulverulenta | Ericaceae
|
| ZEPU3 | Zenobia pulverulenta (Bartr. ex Willd.) Pollard | honeycup | Ericaceae
|
| ZENOB | Zenobia D. Don | honeycup | Ericaceae
|
| ZEATA | Zephyranthes atamasca (L.) Herbert var. atamasca | Atamasco lily | Liliaceae
|
| ZEATT | Zephyranthes atamasca (L.) Herbert var. treatiae (S. Wats.) Meerow | Atamasco lily | Liliaceae
|
| ZEAT | Zephyranthes atamasca (L.) Herbert | Atamasco lily | Liliaceae
|
| ZEBR | Zephyranthes brazosensis (Herbert) Traub | Cooperia drummondii | Liliaceae
|
| ZECA | Zephyranthes candida (Lindl.) Herbert | autumn zephyrlily | Liliaceae
|
| ZECI | Zephyranthes citrina Baker | citron zephyrlily | Liliaceae
|
| ZEDR2 | Zephyranthes drummondii D. Don | Cooperia pedunculata | Liliaceae
|
| ZEGR | Zephyranthes grandiflora Lindl. | rosepink zephyrlily | Liliaceae
|
| ZEIN | Zephyranthes insularum auct. non Hume | Zephyranthes puertoricensis | Liliaceae
|
| ZEJO2 | Zephyranthes jonesii (Cory) Traub | Cooperia jonesii | Liliaceae
|
| ZELO | Zephyranthes longifolia Hemsl. | copper zephyrlily | Liliaceae
|
| ZEPU2 | Zephyranthes puertoricensis Traub | Puerto Rico zephyrlily | Liliaceae
|
| ZEPU | Zephyranthes pulchella J.G. Sm. | showy zephyrlily | Liliaceae
|
| ZERE | Zephyranthes refugiensis F.B. Jones | refugio zephyrlily | Liliaceae
|
| ZERO | Zephyranthes rosea Lindl. | Cuban zephyrlily | Liliaceae
|
| ZESI | Zephyranthes simpsonii Chapman | redmargin zephyrlily | Liliaceae
|
| ZESM2 | Zephyranthes smallii (Alexander) Traub | Cooperia smallii | Liliaceae
|
| ZETE2 | Zephyranthes texana Herbert | Habranthus tubispathus | Liliaceae
|
| ZETR | Zephyranthes treatiae S. Wats. | Zephyranthes atamasca var. treatiae | Liliaceae
|
| ZETU | Zephyranthes tubispatha Herbert | Zephyranthes puertoricensis | Liliaceae
|
| ZEPHY | Zephyranthes Herbert | zephyrlily | Liliaceae
|
| ZEST | Zeuxine strateumatica (L.) Schlechter | soldier's orchid | Orchidaceae
|
| ZEUXI | Zeuxine Lindl. | zeuxine | Orchidaceae
|
| ZEBR2 | Zexmenia brevifolia Gray | Jefea brevifolia | Asteraceae
|
| ZEHI2 | Zexmenia hispida auct. non (Kunth) Gray ex Small | Wedelia texana | Asteraceae
|
| ZEPO2 | Zexmenia podocephala (Gray) Gray | Lasianthaea podocephala | Asteraceae
|
| ZIAL | Zigadenus alpinus Blank. | Zigadenus elegans ssp. elegans | Liliaceae
|
| ZIBR | Zigadenus brevibracteatus (M.E. Jones) Hall | desert deathcamas | Liliaceae
|
| ZIDE | Zigadenus densus (Desr.) Fern. | Osceola's plume | Liliaceae
|
| ZIELE | Zigadenus elegans Pursh ssp. elegans | mountain deathcamas | Liliaceae
|
| ZIELG | Zigadenus elegans Pursh ssp. glaucus (Nutt.) Hult�n | mountain deathcamas | Liliaceae
|
| ZIELG2 | Zigadenus elegans Pursh var. glaucus (Nutt.) Cronq. | Zigadenus elegans ssp. glaucus | Liliaceae
|
| ZIEL2 | Zigadenus elegans Pursh | mountain deathcamas | Liliaceae
|
| ZIEX | Zigadenus exaltatus Eastw. | giant deathcamas | Liliaceae
|
| ZIFO | Zigadenus fontanus Eastw. | Zigadenus micranthus var. fontanus | Liliaceae
|
| ZIFRB | Zigadenus fremontii (Torr.) Torr. ex S. Wats. var. brevibracteatus M.E. Jones | Zigadenus brevibracteatus | Liliaceae
|
| ZIFRI | Zigadenus fremontii (Torr.) Torr. ex S. Wats. var. inezianus Jepson | Zigadenus fremontii | Liliaceae
|
| ZIFRM | Zigadenus fremontii (Torr.) Torr. ex S. Wats. var. minor (Hook. & Arn.) Jepson | Zigadenus fremontii | Liliaceae
|
| ZIFRS | Zigadenus fremontii (Torr.) Torr. ex S. Wats. var. salsus Jepson | Zigadenus fremontii | Liliaceae
|
| ZIFR | Zigadenus fremontii (Torr.) Torr. ex S. Wats. | Fremont's deathcamas | Liliaceae
|
| ZIGL | Zigadenus glaberrimus Michx. | sandbog deathcamas | Liliaceae
|
| ZIGL2 | Zigadenus glaucus Nutt. | Zigadenus elegans ssp. glaucus | Liliaceae
|
| ZIGR2 | Zigadenus gramineus Rydb. | Zigadenus venenosus var. gramineus | Liliaceae
|
| ZIIN | Zigadenus intermedius Rydb. | Zigadenus venenosus var. gramineus | Liliaceae
|
| ZILE | Zigadenus leimanthoides Gray | pinebarren deathcamas | Liliaceae
|
| ZIMIF2 | Zigadenus micranthus Eastw. var. fontanus (Eastw.) O.S. Walsh ex McNeal | smallflower deathcamas | Liliaceae
|
| ZIMIM | Zigadenus micranthus Eastw. var. micranthus | smallflower deathcamas | Liliaceae
|