| Symbol | Scientific name | Common name/Accepted name (for synonyms) | Family |
| HADI2 | Hackelia diffusa (Lehm.) I.M. Johnston | spreading stickseed | Boraginaceae
|
| HAFL2 | Hackelia floribunda (Lehm.) I.M. Johnston | manyflower stickseed | Boraginaceae
|
| HAGR10 | Hackelia gracilenta (Eastw.) I.M. Johnston | Mesa Verde stickseed | Boraginaceae
|
| HAGR2 | Hackelia grisea (Woot. & Standl.) I.M. Johnston | Hackelia besseyi | Boraginaceae
|
| HAHI2 | Hackelia hirsuta (Woot. & Standl.) I.M. Johnston | New Mexico stickseed | Boraginaceae
|
| HAHID | Hackelia hispida (Gray) I.M. Johnston var. disjuncta R.L. Carr | rough stickseed | Boraginaceae
|
| HAHIH | Hackelia hispida (Gray) I.M. Johnston var. hispida | showy stickseed | Boraginaceae
|
| HAHI3 | Hackelia hispida (Gray) I.M. Johnston | showy stickseed | Boraginaceae
|
| HAIB | Hackelia ibapensis L.& J. Shultz | Ibapah tickweed | Boraginaceae
|
| HAJE | Hackelia jessicae (McGregor) Brand | Hackelia micrantha | Boraginaceae
|
| HALE4 | Hackelia leptophylla (Rydb.) I.M. Johnston | Hackelia floribunda | Boraginaceae
|
| HALO | Hackelia longituba I.M. Johnston | Hackelia velutina | Boraginaceae
|
| HAMI | Hackelia micrantha (Eastw.) J.L. Gentry | Jessica sticktight | Boraginaceae
|
| HAMU | Hackelia mundula (Jepson) Ferris | pink stickseed | Boraginaceae
|
| HANE | Hackelia nervosa (Kellogg) I.M. Johnston | Sierra stickseed | Boraginaceae
|
| HAOP2 | Hackelia ophiobia R.L. Carr | Owyhee River stickseed | Boraginaceae
|
| HAPAH | Hackelia patens (Nutt.) I.M. Johnston var. harrisonii J.L. Gentry | Harrison's stickseed | Boraginaceae
|
| HAPAP | Hackelia patens (Nutt.) I.M. Johnston var. patens | spotted stickseed | Boraginaceae
|
| HAPAS | Hackelia patens (Nutt.) I.M. Johnston var. semiglabra Cronq. | Hackelia cronquistii | Boraginaceae
|
| HAPA | Hackelia patens (Nutt.) I.M. Johnston | spotted stickseed | Boraginaceae
|
| HAPIJ | Hackelia pinetorum (Greene ex Gray) I.M. Johnston var. jonesii J.L. Gentry | Jones' stickseed | Boraginaceae
|
| HAPIP | Hackelia pinetorum (Greene ex Gray) I.M. Johnston var. pinetorum | Livermore stickseed | Boraginaceae
|
| HAPI2 | Hackelia pinetorum (Greene ex Gray) I.M. Johnston | Livermore stickseed | Boraginaceae
|
| HASA4 | Hackelia saxatilis (Piper) Brand | Hackelia diffusa var. diffusa | Boraginaceae
|
| HASE | Hackelia setosa (Piper) I.M. Johnston | bristly stickseed | Boraginaceae
|
| HASH | Hackelia sharsmithii I.M. Johnston | Sharsmith's stickseed | Boraginaceae
|
| HAURD | Hackelia ursina (Greene ex Gray) I.M. Johnston var. diaboli J.L. Gentry | Chihuahuan stickseed | Boraginaceae
|
| HAURP | Hackelia ursina (Greene ex Gray) I.M. Johnston var. pustulata (J.F. Macbr.) J.L. Gentry | Chihuahuan stickseed | Boraginaceae
|
| HAURU | Hackelia ursina (Greene ex Gray) I.M. Johnston var. ursina | Chihuahuan stickseed | Boraginaceae
|
| HAUR | Hackelia ursina (Greene ex Gray) I.M. Johnston | Chihuahuan stickseed | Boraginaceae
|
| HAVE | Hackelia velutina (Piper) I.M. Johnston | velvet stickseed | Boraginaceae
|
| HAVE4 | Hackelia venusta (Piper) St. John | lesser showy stickseed | Boraginaceae
|
| HAVI2 | Hackelia virginiana (L.) I.M. Johnston | beggarslice | Boraginaceae
|
| HACKE | Hackelia Opiz | stickseed | Boraginaceae
|
| HAGR3 | Hackelochloa granularis (L.) Kuntze | pitscale grass | Poaceae
|
| HACKE2 | Hackelochloa Kuntze | pitscale grass | Poaceae
|
| HAKA | Haemanthus katherinae Baker | Scadoxus multiflorus ssp. katherinae | Liliaceae
|
| HAAC3 | Haematomma accolens (Stirton) Hillm. | bloodstain lichen | Haematommataceae
|
| HAAM3 | Haematomma americanum Kalb & Staiger | bloodstain lichen | Haematommataceae
|
| HACA8 | Haematomma californicum Sigal & D. Toren | Ophioparma rubricosa | Ophioparmaceae
|
| HACI8 | Haematomma cismonicum Beltr. | Loxospora cismonica | Haematommataceae
|
| HAEL4 | Haematomma elatinum (Ach.) A. Massal. | Loxospora elatina | Haematommataceae
|
| HAFE | Haematomma fenzlianum A. Massal. | bloodstain lichen | Haematommataceae
|
| HAFL7 | Haematomma flexuosum Hillm. | bloodstain lichen | Haematommataceae
|
| HALA7 | Haematomma lapponicum Rasanen | Ophioparma lapponica | Ophioparmaceae
|
| HAOCP | Haematomma ochroleucum (Necker) J. R. Laundon var. porphyrium (Pers.) J. R. Laundon | yellow bloodstain lichen | Haematommataceae
|
| HAOC3 | Haematomma ochroleucum (Necker) J. R. Laundon | yellow bloodstain lichen | Haematommataceae
|
| HAOC2 | Haematomma ochrophaeum (Tuck.) A. Massal. | Loxospora ochrophaea | Haematommataceae
|
| HAPA12 | Haematomma pacificum Hasse | Ophioparma rubricosa | Ophioparmaceae
|
| HAPE6 | Haematomma persoonii (Fee) A. Massal. | bloodstain lichen | Haematommataceae
|
| HAPO4 | Haematomma porphyrium (Pers.) Zopf | Haematomma ochroleucum var. porphyrium | Haematommataceae
|
| HAPU3 | Haematomma puniceum auct. | Haematomma persoonii | Haematommataceae
|
| HAPU2 | Haematomma pustulatum Brodo & Culb. | Loxospora pustulata | Haematommataceae
|
| HARA4 | Haematomma rappii Zahlbr. | Schismatomma rappii | Opegraphaceae
|
| HARU2 | Haematomma rufidulum (Fee) A. Massal. | bloodstain lichen | Haematommataceae
|
| HASU4 | Haematomma subpuniceum (Fee) de Lesd. | Haematomma fenzlianum | Haematommataceae
|
| HAVE3 | Haematomma ventosum (L.) A. Massal. | Ophioparma lapponica | Ophioparmaceae
|
| HAEMA3 | Haematomma A. Massal. | bloodstain lichen | Haematommataceae
|
| HACA2 | Haematoxylum campechianum L. | bloodwoodtree | Fabaceae
|
| HAEMA2 | Haematoxylum L. | haematoxylum | Fabaceae
|
| HAPO3 | Haemocharis portoricensis Krug & Urban | Laplacea portoricensis | Theaceae
|
| HAOB3 | Haenianthus obovatus Krug & Urban | Haenianthus salicifolius var. obovatus | Oleaceae
|
| HASAO | Haenianthus salicifolius Griseb. var. obovatus (Krug & Urban) Knobl. | palo de hueso | Oleaceae
|
| HASA2 | Haenianthus salicifolius Griseb. | palo de hueso | Oleaceae
|
| HAENI | Haenianthus Griseb. | haenianthus | Oleaceae
|
| HABAP | Hafellia bahiana (Malme) Sheard var. pleiotropa (Malme) Sheard | | Physciaceae
|
| HABA4 | Hafellia bahiana (Malme) Sheard | | Physciaceae
|
| HACA9 | Hafellia callispora (C. Knight) H. Mayrh. & Sheard | | Physciaceae
|
| HAFO2 | Hafellia fosteri Imshaug & Sheard | | Physciaceae
|
| HAPA13 | Hafellia parastata (Nyl.) Kalb | | Physciaceae
|
| HAFEL | Hafellia Kalb | hafellia | Physciaceae
|
| HAPA14 | Hafellnera parasemella (Nyl.) Houmeau & Roux | | Schaereriaceae
|
| HAFEL2 | Hafellnera Houmeau & Roux | hafellnera | Schaereriaceae
|
| HACY | Hainardia cylindrica (Willd.) W. Greuter | barbgrass | Poaceae
|
| HAINA | Hainardia W. Greuter | barbgrass | Poaceae
|
| HARO2 | Hakea rostrata F. Muell. | beaked pincushion tree | Proteaceae
|
| HAKEA | Hakea Schrad. | pincushion tree | Proteaceae
|
| HAMA9 | Hakonechloa macra (Munro) Makino | Hakone grass | Poaceae
|
| HAKON | Hakonechloa (Munro) Makino | Hakone grass | Poaceae
|
| HALU2 | Halea ludoviciana Torr. & Gray | Tetragonotheca ludoviciana | Asteraceae
|
| HARE4 | Halea repanda Buckl. | Tetragonotheca repanda | Asteraceae
|
| HAAL6 | Halecania alpivaga (Th. Fr.) M. Mayrh. | | Catillariaceae
|
| HAVI10 | Halecania viridescens Coppins & P. James | | Catillariaceae
|
| HALEC | Halecania M. Mayrh. | halecania | Catillariaceae
|
| HADE2 | Halenia deflexa (Sm.) Griseb. | American spurred gentian | Gentianaceae
|
| HARE2 | Halenia recurva (Sm.) Allen | Mt. Graham spurred gentian | Gentianaceae
|
| HALEN | Halenia Borkh. | spurred gentian | Gentianaceae
|
| HACYS | Halerpestes cymbalaria (Pursh) Greene ssp. saximontana (Fern.) Moldenke | Ranunculus cymbalaria | Ranunculaceae
|
| HACY2 | Halerpestes cymbalaria (Pursh) Greene | Ranunculus cymbalaria | Ranunculaceae
|
| HACAM2 | Halesia carolina L. var. monticola Rehd. | Halesia tetraptera var. monticola | Styracaceae
|
| HACA3 | Halesia carolina L. | Carolina silverbell | Styracaceae
|
| HADIM2 | Halesia diptera Ellis var. magniflora Godfrey | Halesia diptera | Styracaceae
|
| HADI3 | Halesia diptera Ellis | two-wing silverbell | Styracaceae
|
| HAMOV | Halesia monticola (Rehd.) Sarg. var. vestita Sarg. | Halesia tetraptera var. monticola | Styracaceae
|
| HAMO3 | Halesia monticola (Rehd.) Sarg. | Halesia tetraptera var. monticola | Styracaceae
|
| HAPA2 | Halesia parviflora Michx. | Halesia carolina | Styracaceae
|
| HATEM | Halesia tetraptera Ellis var. monticola (Rehd.) Reveal & Seldin | mountain silverbell | Styracaceae
|
| HATET | Halesia tetraptera Ellis var. tetraptera | mountain silverbell | Styracaceae
|
| HATE3 | Halesia tetraptera Ellis | mountain silverbell | Styracaceae
|
| HALES | Halesia Ellis ex L. | silverbell | Styracaceae
|
| HAHA8 | Halimodendron halodendron (L. f.) Voss | common salttree | Fabaceae
|