| Symbol | Scientific name | Common name/Accepted name (for synonyms) | Family |
| HIPPO2 | Hippocratea L. | hippocratea | Hippocrateaceae
|
| HICO6 | Hippocrepis commutata Pau | hippocrepis | Fabaceae
|
| HICO3 | Hippocrepis comosa L. | horseshoe vetch | Fabaceae
|
| HIPPO5 | Hippocrepis L. | hippocrepis | Fabaceae
|
| HIMA2 | Hippomane mancinella L. | manchineel | Euphorbiaceae
|
| HIPPO | Hippomane L. | hippomane | Euphorbiaceae
|
| HIRH80 | Hippophae rhamnoides L. | seabuckthorn | Elaeagnaceae
|
| HIPPO4 | Hippophae L. | seabuckthorn | Elaeagnaceae
|
| HILE3 | Hipposelinum levisticum (L.) Britt. & Rose | Levisticum officinale | Apiaceae
|
| HIMO2 | Hippuris montana Ledeb. | mountain mare's-tail | Hippuridaceae
|
| HITE | Hippuris tetraphylla L. f. | fourleaf mare's-tail | Hippuridaceae
|
| HIVU2 | Hippuris vulgaris L. | common mare's-tail | Hippuridaceae
|
| HIPPU | Hippuris L. | mare's-tail | Hippuridaceae
|
| HIBE2 | Hiptage benghalensis (L.) Kurz | hiptage | Malpighiaceae
|
| HIPTA | Hiptage Gaertn., nom. cons. | hiptage | Malpighiaceae
|
| HIPLC | Hirculus platysepalus (Trautv.) W.A. Weber ssp. crandallii (Gandog.) W.A. Weber | Saxifraga flagellaris ssp. crandallii | Saxifragaceae
|
| HIPL3 | Hirculus platysepalus (Trautv.) W.A. Weber | Saxifraga platysepala | Saxifragaceae
|
| HIPR5 | Hirculus prorepens (Fisch. ex Sternb.) A.& D. L�ve | Saxifraga hirculus ssp. propinqua | Saxifragaceae
|
| HISEC | Hirculus serpyllifolius (Pursh) W.A. Weber ssp. chrysanthus (Gray) W.A. Weber | Saxifraga chrysantha | Saxifragaceae
|
| HISE2 | Hirculus serpyllifolius (Pursh) W.A. Weber | Saxifraga serpyllifolia | Saxifragaceae
|
| HIIN3 | Hirschfeldia incana (L.) Lagr�ze-Fossat | shortpod mustard | Brassicaceae
|
| HIRSC | Hirschfeldia Moench | hirschfeldia | Brassicaceae
|
| HIAM2 | Hirtella americana Jacq., non L. | Hirtella triandra | Chrysobalanaceae
|
| HIJA2 | Hirtella jamaicensis Urban | Hirtella triandra | Chrysobalanaceae
|
| HIMU5 | Hirtella multiflora Urban | Hirtella triandra | Chrysobalanaceae
|
| HIPO2 | Hirtella portoricensis Humb. & Bonpl. | Hirtella rugosa | Chrysobalanaceae
|
| HIRU2 | Hirtella rugosa Thuill. ex Pers. | teta de burra cinarron | Chrysobalanaceae
|
| HITR3 | Hirtella triandra Sw. | pigeonberry | Chrysobalanaceae
|
| HIRTE | Hirtella L. | hirtella | Chrysobalanaceae
|
| HIIN2 | Histiopteris incisa (Thunb.) J. Sm. | batwing fern | Dennstaedtiaceae
|
| HISTI | Histiopteris (J.G. Agardh) J. Sm. | histiopteris | Dennstaedtiaceae
|
| HICA11 | Hitchenia caulina (J. Graham) Baker | chavar | Zingiberaceae
|
| HITCH | Hitchenia Wallich | hitchenia | Zingiberaceae
|
| HOCH | Hobsonia christiansenii B. L. Brady & D. Hawksw. | | Uncertain Lichen Family
|
| HOBSO | Hobsonia Massee | hobsonia | Uncertain Lichen Family
|
| HOHE5 | Hodgsonia heteroclita (Roxb.) Hook f. & Thomson | Chinese lardplant | Cucurbitaceae
|
| HODGS | Hodgsonia Hook. f. & Thomson | hodgsonia | Cucurbitaceae
|
| HOLA6 | Hoffmania lanceolata Griseb. | Lasianthus lanceolatus | Rubiaceae
|
| HOBR4 | Hoffmannseggia brachycarpa Gray | Caesalpinia brachycarpa | Fabaceae
|
| HOCA8 | Hoffmannseggia caudata Gray | Caesalpinia caudata | Fabaceae
|
| HODEC | Hoffmannseggia densiflora Benth. var. capitata Fisher | Hoffmannseggia glauca | Fabaceae
|
| HODED | Hoffmannseggia densiflora Benth. var. demissa (Gray) Fisher | Hoffmannseggia glauca | Fabaceae
|
| HODEP | Hoffmannseggia densiflora Benth. var. pringlei Fisher | Hoffmannseggia glauca | Fabaceae
|
| HODES | Hoffmannseggia densiflora Benth. var. stricta (Benth.) Fisher | Hoffmannseggia glauca | Fabaceae
|
| HODE | Hoffmannseggia densiflora Benth. | Hoffmannseggia glauca | Fabaceae
|
| HODR | Hoffmannseggia drepanocarpa Gray | Caesalpinia drepanocarpa | Fabaceae
|
| HODR3 | Hoffmannseggia drummondii Torr. & Gray | Caesalpinia drummondii | Fabaceae
|
| HOFA3 | Hoffmannseggia falcaria Cav. | Hoffmannseggia glauca | Fabaceae
|
| HOGL2 | Hoffmannseggia glauca (Ortega) Eifert | Indian rushpea | Fabaceae
|
| HOJA3 | Hoffmannseggia jamesii Torr. & Gray | Caesalpinia jamesii | Fabaceae
|
| HOME2 | Hoffmannseggia melanosticta (Schauer) Gray | Caesalpinia wootonii | Fabaceae
|
| HOMI5 | Hoffmannseggia microphylla Torr. | Caesalpinia virgata | Fabaceae
|
| HOOX | Hoffmannseggia oxycarpa Benth. ex Gray | sharppod rushpea | Fabaceae
|
| HOPA7 | Hoffmannseggia parryi (Fisher) B.L. Turner | Caesalpinia parryi | Fabaceae
|
| HORE | Hoffmannseggia repens (Eastw.) Cockerell | Caesalpinia repens | Fabaceae
|
| HOTE | Hoffmannseggia tenella Tharp & Williams | slender rushpea | Fabaceae
|
| HOFFM | Hoffmannseggia Cav. | rushpea | Fabaceae
|
| HOPL4 | Hofmeisteria pluriseta Gray | Pleurocoronis pluriseta | Asteraceae
|
| HOAN | Hohenbergia antillana Mez | Antilles lacebark | Bromeliaceae
|
| HOAT | Hohenbergia attenuata Britt. | longtip lacebark | Bromeliaceae
|
| HOPO2 | Hohenbergia portoricensis Mez | Puerto Rico lacebark | Bromeliaceae
|
| HOHEN | Hohenbergia J.A. Schultes ex J.A. & J.H. Schultes | lacebark | Bromeliaceae
|
| HOHA3 | Hoita hallii Rydb. | Rupertia hallii | Fabaceae
|
| HOLO2 | Hoita longiloba Rydb. | Hoita macrostachya | Fabaceae
|
| HOMA4 | Hoita macrostachya (DC.) Rydb. | large leather-root | Fabaceae
|
| HOOR | Hoita orbicularis (Lindl.) Rydb. | roundleaf leather-root | Fabaceae
|
| HORH | Hoita rhombifolia (Torr.) Rydb. | Hoita macrostachya | Fabaceae
|
| HOST3 | Hoita strobilina (Hook. & Arn.) Rydb. | Loma prieta | Fabaceae
|
| HOVI3 | Hoita villosa Greene | Hoita macrostachya | Fabaceae
|
| HOITA | Hoita Rydb. | leather-root | Fabaceae
|
| HOEM | Holacantha emoryi Gray | Castela emoryi | Simaroubaceae
|
| HOST2 | Holacantha stewartii C.H. Muell. | Stewart's crucifixionthorn | Simaroubaceae
|
| HOLAC | Holacantha Gray | holacantha | Simaroubaceae
|
| HOAN3 | Holarrhena antidysenterica (Roxb. ex Fleming) Wallich ex A. DC. | tellicherry bark | Apocynaceae
|
| HOFE | Holarrhena febrifuga Klotzsch | Holarrhena pubescens | Apocynaceae
|
| HOFL2 | Holarrhena floribunda (G. Don) Durand & Schinz | false rubber tree | Apocynaceae
|
| HOPU7 | Holarrhena pubescens (Buch.-Ham.) Wallich ex G. Don | holarrhena | Apocynaceae
|
| HOWU | Holarrhena wulfsbergii Stapf | Holarrhena floribunda | Apocynaceae
|
| HOLAR | Holarrhena R. Br. | holarrhena | Apocynaceae
|
| HODI3 | Holcophacos distortus (Torr. & Gray) Rydb. | Astragalus distortus var. distortus | Fabaceae
|
| HOBI | Holcus bicolor L. | Sorghum bicolor ssp. bicolor | Poaceae
|
| HOHA | Holcus halepensis L. | Sorghum halepense | Poaceae
|
| HOLA | Holcus lanatus L. | common velvetgrass | Poaceae
|
| HOMO | Holcus mollis L. | creeping velvetgrass | Poaceae
|
| HOOD | Holcus odoratus L. | Hierochloe odorata | Poaceae
|
| HOPE3 | Holcus pertusus L. | Bothriochloa pertusa | Poaceae
|
| HOSO | Holcus sorghum L. | Sorghum bicolor ssp. bicolor | Poaceae
|
| HOST4 | Holcus striatus L. | Sacciolepis striata | Poaceae
|
| HOLCU | Holcus L. | velvetgrass | Poaceae
|
| HOLA2 | Hollisteria lanata S. Wats. | false spikeflower | Polygonaceae
|
| HOLLI | Hollisteria S. Wats. | hollisteria | Polygonaceae
|
| HOPE2 | Holmgrenanthe petrophila (Coville & Morton) Elisens | rocklady | Scrophulariaceae
|
| HOLMG | Holmgrenanthe Elisens | rocklady | Scrophulariaceae
|
| HOAC3 | Holmgrenia acuminata (Bryhn) Grout | Orthothecium acuminatum | Hypnaceae
|
| HOCH2 | Holmgrenia chrysea (Schwaegr. in Schultes) Lindb. | Orthothecium chryseum var. chryseum | Hypnaceae
|
| HODI5 | Holmgrenia diminutiva Grout | Orthothecium diminutivum | Hypnaceae
|
| HOIN6 | Holmgrenia intricata (Hartm.) Lindb. | Orthothecium intricatum | Hypnaceae
|
| HORU4 | Holmgrenia rufescens (Brid.) Lindb. | Orthothecium rufescens | Hypnaceae
|
| HOST7 | Holmgrenia stricta (Lor.) Grout | Orthothecium strictum | Hypnaceae
|
| HOSA2 | Holmskioldia sanguinea Retz. | Chinese hatplant | Verbenaceae
|
| HOLMS | Holmskioldia Retz. | holmskioldia | Verbenaceae
|