| Symbol | Scientific name | Common name/Accepted name (for synonyms) | Family |
| ZIMO | Zigadenus mogollonensis W.J. Hess & R.C. Sivinski | Mogoll deathcamas | Liliaceae
|
| ZIMU2 | Zigadenus muscitoxicus (Walt.) Regel | Amianthium muscitoxicum | Liliaceae
|
| ZINU | Zigadenus nuttallii (Gray) S. Wats. | Nuttall's deathcamas | Liliaceae
|
| ZIPA2 | Zigadenus paniculatus (Nutt.) S. Wats. | foothill deathcamas | Liliaceae
|
| ZIVA | Zigadenus vaginatus (Rydb.) J.F. Macbr. | sheathed deathcamas | Liliaceae
|
| ZIVEG | Zigadenus venenosus S. Wats. var. gramineus (Rydb.) Walsh ex M.E. Peck | grassy deathcamas | Liliaceae
|
| ZIVEM | Zigadenus venenosus S. Wats. var. micranthus (Eastw.) Jepson | Zigadenus micranthus var. micranthus | Liliaceae
|
| ZIVEV | Zigadenus venenosus S. Wats. var. venenosus | meadow deathcamas | Liliaceae
|
| ZIVE | Zigadenus venenosus S. Wats. | meadow deathcamas | Liliaceae
|
| ZIVI | Zigadenus virescens (Kunth) J.F. Macbr. | green deathcamas | Liliaceae
|
| ZIGAD | Zigadenus Michx. | deathcamas | Liliaceae
|
| ZICA | Zingiber cassumunar Roxb. | Zingiber purpureum | Zingiberaceae
|
| ZIMI4 | Zingiber mioga (Thunb.) Roscoe | Mioga ginger | Zingiberaceae
|
| ZIOF | Zingiber officinale Roscoe | garden ginger | Zingiberaceae
|
| ZIPU2 | Zingiber purpureum Roscoe | Cassumunar ginger | Zingiberaceae
|
| ZIZE | Zingiber zerumbet (L.) Sm. | bitter ginger | Zingiberaceae
|
| ZIZI2 | Zingiber zingiber (L.) Karst. | Zingiber officinale | Zingiberaceae
|
| ZINGI | Zingiber P. Mill. | ginger | Zingiberaceae
|
| ZIAC | Zinnia acerosa (DC.) Gray | desert zinnia | Asteraceae
|
| ZIAN2 | Zinnia angustifolia Kunth | narrowlead zinnia | Asteraceae
|
| ZIAN | Zinnia anomala Gray | shortray zinnia | Asteraceae
|
| ZIEL | Zinnia elegans Jacq. | Zinnia violacea | Asteraceae
|
| ZIGR | Zinnia grandiflora Nutt. | Rocky Mountain zinnia | Asteraceae
|
| ZIMAP | Zinnia maritima Kunth var. palmeri (Gray) B.L. Turner | Palmer's zinnia | Asteraceae
|
| ZIMA2 | Zinnia maritima Kunth | Palmer's zinnia | Asteraceae
|
| ZIMU3 | Zinnia multiflora L. | Zinnia peruviana | Asteraceae
|
| ZIPA4 | Zinnia palmeri Gray | Zinnia maritima var. palmeri | Asteraceae
|
| ZIPA5 | Zinnia pauciflora L. | Zinnia peruviana | Asteraceae
|
| ZIPE | Zinnia peruviana (L.) L. | Peruvian zinnia | Asteraceae
|
| ZIPU | Zinnia pumila Gray | Zinnia acerosa | Asteraceae
|
| ZIVI2 | Zinnia violacea Cav. | elegant zinnia | Asteraceae
|
| ZINNI | Zinnia L. | zinnia | Asteraceae
|
| ZIAQA3 | Zizania aquatica L. ssp. angustifolia (A.S. Hitchc.) Tzvelev | Zizania palustris var. palustris | Poaceae
|
| ZIAQA | Zizania aquatica L. var. angustifolia A.S. Hitchc. | Zizania palustris var. palustris | Poaceae
|
| ZIAQA2 | Zizania aquatica L. var. aquatica | annual wildrice | Poaceae
|
| ZIAQB | Zizania aquatica L. var. brevis Fassett | annual wildrice | Poaceae
|
| ZIAQI | Zizania aquatica L. var. interior Fassett | Zizania palustris var. interior | Poaceae
|
| ZIAQS | Zizania aquatica L. var. subbrevis Boivin | Zizania aquatica var. aquatica | Poaceae
|
| ZIAQ | Zizania aquatica L. | annual wildrice | Poaceae
|
| ZICA2 | Zizania caduciflora (Trin.) Hand.-Mazz. | Zizania latifolia | Poaceae
|
| ZILA3 | Zizania latifolia (Griseb.) Turcz. ex Stapf | Manchurian wildrice | Poaceae
|
| ZIMI3 | Zizania miliacea Michx. | Zizaniopsis miliacea | Poaceae
|
| ZIPAI | Zizania palustris L. var. interior (Fassett) Dore | northern wildrice | Poaceae
|
| ZIPAP | Zizania palustris L. var. palustris | northern wildrice | Poaceae
|
| ZIPA3 | Zizania palustris L. | northern wildrice | Poaceae
|
| ZITE | Zizania texana A.S. Hitchc. | Texas wildrice | Poaceae
|
| ZIZAN | Zizania L. | wildrice | Poaceae
|
| ZIMI | Zizaniopsis miliacea (Michx.) Doell & Aschers. | giant cutgrass | Poaceae
|
| ZIZAN2 | Zizaniopsis Doell & Aschers. | cutgrass | Poaceae
|
| ZIAPO | Zizia aptera (Gray) Fern. var. occidentalis Fern. | Zizia aptera | Apiaceae
|
| ZIAP | Zizia aptera (Gray) Fern. | meadow zizia | Apiaceae
|
| ZIAR | Zizia arenicola Rose | Zizia trifoliata | Apiaceae
|
| ZIAU | Zizia aurea (L.) W.D.J. Koch | golden zizia | Apiaceae
|
| ZIBE | Zizia bebbii (Coult. & Rose) Britt. | Zizia trifoliata | Apiaceae
|
| ZICO | Zizia cordata W.D.J. Koch ex DC. | Zizia aptera | Apiaceae
|
| ZILA2 | Zizia latifolia Small | Zizia trifoliata | Apiaceae
|
| ZITR | Zizia trifoliata (Michx.) Fern. | meadow alexanders | Apiaceae
|
| ZIZIA | Zizia W.D.J. Koch | zizia | Apiaceae
|
| ZIPU3 | Ziziphora pulegioides (L.) Desf. | Hedeoma pulegioides | Lamiaceae
|
| ZICE | Ziziphus celata Judd & Hall | Florida jujube | Rhamnaceae
|
| ZIJU2 | Ziziphus jujuba (L.) Lam., non P. Mill. | Ziziphus mauritiana | Rhamnaceae
|
| ZIJU | Ziziphus jujuba P. Mill. | Ziziphus zizyphus | Rhamnaceae
|
| ZILO | Ziziphus lotus (L.) Lam. | lotus jujube | Rhamnaceae
|
| ZIMA | Ziziphus mauritiana Lam. | Indian jujube | Rhamnaceae
|
| ZINU2 | Ziziphus nummularia (Burman f.) Wight & Arn. | jujube | Rhamnaceae
|
| ZIOBC | Ziziphus obtusifolia (Hook. ex Torr. & Gray) Gray var. canescens (Gray) M.C. Johnston | lotebush | Rhamnaceae
|
| ZIOBO | Ziziphus obtusifolia (Hook. ex Torr. & Gray) Gray var. obtusifolia | lotebush | Rhamnaceae
|
| ZIOB | Ziziphus obtusifolia (Hook. ex Torr. & Gray) Gray | lotebush | Rhamnaceae
|
| ZIPA | Ziziphus parryi Torr. | Parry's jujube | Rhamnaceae
|
| ZIRE | Ziziphus reticulata (Vahl) DC. | cacao rojo | Rhamnaceae
|
| ZIRI | Ziziphus rignonii Delponte | soana | Rhamnaceae
|
| ZITA | Ziziphus taylorii (Britt.) M.C. Johnston | Taylor's jujube | Rhamnaceae
|
| ZIZI | Ziziphus zizyphus (L.) Karst. | common jujube | Rhamnaceae
|
| ZIZIP | Ziziphus P. Mill. | jujube | Rhamnaceae
|
| ZOEL | Zollikoferia elquiensis Phil. | Malacothrix coulteri | Asteraceae
|
| ZOBR | Zornia bracteata J.F. Gmel. | viperina | Fabaceae
|
| ZODIL | Zornia diphylla (L.) Pers. var. leptophylla Benth. | Zornia leptophylla | Fabaceae
|
| ZODI80 | Zornia diphylla auct. non Pers. | Zornia gemella | Fabaceae
|
| ZOGE | Zornia gemella Vogel | dos hoja zazabacoa de dos hojas | Fabaceae
|
| ZOLE | Zornia leptophylla (Benth.) Pittier | horsekiller | Fabaceae
|
| ZORE | Zornia reticulata Sm. | neto hoja zarzabacoa de dos hojas | Fabaceae
|
| ZORNI | Zornia J.F. Gmel. | zornia | Fabaceae
|
| ZOAM | Zostera americana den Hartog | Zostera japonica | Zosteraceae
|
| ZOJA2 | Zostera japonica Aschers. & Graebn. | dwarf eelgrass | Zosteraceae
|
| ZOMAL | Zostera marina L. var. latifolia Morong | Zostera marina | Zosteraceae
|
| ZOMAS | Zostera marina L. var. stenophylla Aschers. & Graebn. | Zostera marina | Zosteraceae
|
| ZOMA | Zostera marina L. | seawrack | Zosteraceae
|
| ZONA | Zostera nana Roth | Zostera japonica | Zosteraceae
|
| ZOPA | Zostera pacifica L. | Zostera marina | Zosteraceae
|
| ZOSTE | Zostera L. | eelgrass | Zosteraceae
|
| ZODU | Zosterella dubia (Jacq.) Small | Heteranthera dubia | Pontederiaceae
|
| ZOLO | Zosterella longituba Alexander | Heteranthera dubia | Pontederiaceae
|
| ZOJA | Zoysia japonica Steud. | Korean lawngrass | Poaceae
|
| ZOMAT2 | Zoysia matrella (L.) Merr. ssp. tenuifolia (Willd. ex Thiele) T. Koyama | Zoysia tenuifolia | Poaceae
|
| ZOMAM | Zoysia matrella (L.) Merr. var. matrella | Manila grass | Poaceae
|
| ZOMAP | Zoysia matrella (L.) Merr. var. pacifica Gouds. | Manila grass | Poaceae
|
| ZOMAT | Zoysia matrella (L.) Merr. var. tenuifolia (Willd. ex Thiele) Sasaki | Zoysia tenuifolia | Poaceae
|
| ZOMA2 | Zoysia matrella (L.) Merr. | Manila grass | Poaceae
|
| ZOTE | Zoysia tenuifolia Willd. ex Thiele | Mascarene grass | Poaceae
|
| ZOYSI | Zoysia Willd. | lawngrass | Poaceae
|
| ZUAR | Zuckia arizonica Standl. | Zuckia brandegeei var. arizonica | Chenopodiaceae
|