| Symbol | Scientific name | Common name/Accepted name (for synonyms) | Family |
| HESCA | Helianthemum scoparium Nutt. var. aldersonii (Greene) Munz | Helianthemum scoparium | Cistaceae
|
| HESCV | Helianthemum scoparium Nutt. var. vulgare Jepson | Helianthemum scoparium | Cistaceae
|
| HESC2 | Helianthemum scoparium Nutt. | Bisbee Peak rushrose | Cistaceae
|
| HESU2 | Helianthemum suffrutescens Schreib. | Helianthemum scoparium | Cistaceae
|
| HETH3 | Helianthemum thyrsoideum Barnh. | Helianthemum nashii | Cistaceae
|
| HELIA2 | Helianthemum P. Mill. | frostweed | Cistaceae
|
| HEPA21 | Helianthium parvulum (Engelm.) Britt. | Echinodorus tenellus | Alismataceae
|
| HETE13 | Helianthium tenellum Britt. | Echinodorus tenellus | Alismataceae
|
| HEAG | Helianthus agrestis Pollard | southeastern sunflower | Asteraceae
|
| HEAL7 | Helianthus alienus E.E. Wats. | Helianthus giganteus | Asteraceae
|
| HEAM7 | Helianthus �ambiguus (Gray) Britt. (pro sp.) | | Asteraceae
|
| HEANP | Helianthus angustifolius L. var. planifolius Fern. | Helianthus angustifolius | Asteraceae
|
| HEAN2 | Helianthus angustifolius L. | swamp sunflower | Asteraceae
|
| HEANJ | Helianthus annuus L. ssp. jaegeri (Heiser) Heiser | Helianthus annuus | Asteraceae
|
| HEANL | Helianthus annuus L. ssp. lenticularis (Dougl. ex Lindl.) Cockerell | Helianthus annuus | Asteraceae
|
| HEANT | Helianthus annuus L. ssp. texanus Heiser | Helianthus annuus | Asteraceae
|
| HEANL2 | Helianthus annuus L. var. lenticularis (Dougl. ex Lindl.) Steyermark | Helianthus annuus | Asteraceae
|
| HEANM | Helianthus annuus L. var. macrocarpus (DC.) Cockerell | Helianthus annuus | Asteraceae
|
| HEANT2 | Helianthus annuus L. var. texanus (Heiser) Shinners | Helianthus annuus | Asteraceae
|
| HEAN3 | Helianthus annuus L. | common sunflower | Asteraceae
|
| HEAN4 | Helianthus anomalus Blake | western sunflower | Asteraceae
|
| HEAR3 | Helianthus argophyllus Torr. & Gray | silverleaf sunflower | Asteraceae
|
| HEAR14 | Helianthus aridus Rydb. | Helianthus annuus | Asteraceae
|
| HEAR15 | Helianthus aristatus Ell. | Verbesina aristata | Asteraceae
|
| HEAR8 | Helianthus arizonensis R.C. Jackson | Arizona sunflower | Asteraceae
|
| HEATA | Helianthus atrorubens L. var. alsodes Fern. | Helianthus atrorubens | Asteraceae
|
| HEATP | Helianthus atrorubens L. var. pubescens Kuntze | Helianthus silphioides | Asteraceae
|
| HEAT | Helianthus atrorubens L. | purpledisk sunflower | Asteraceae
|
| HEBO3 | Helianthus bolanderi Gray | serpentine sunflower | Asteraceae
|
| HEBO6 | Helianthus borealis E.E. Wats. | Helianthus giganteus | Asteraceae
|
| HEBR5 | Helianthus �brevifolius E.E. Wats. (pro sp.) | | Asteraceae
|
| HECA5 | Helianthus californicus DC. | California sunflower | Asteraceae
|
| HECA25 | Helianthus canescens (Gray) S. Wats. | Helianthus niveus ssp. canescens | Asteraceae
|
| HECA28 | Helianthus canus (Britt.) Woot. & Standl. | Helianthus niveus ssp. canescens | Asteraceae
|
| HECA14 | Helianthus carnosus Small | lakeside sunflower | Asteraceae
|
| HECI | Helianthus ciliaris DC. | Texas blueweed | Asteraceae
|
| HECIS2 | Helianthus cinereus Torr. & Gray var. sullivantii Torr. & Gray | Helianthus cinereus | Asteraceae
|
| HECI3 | Helianthus �cinereus Torr. & Gray (pro sp.) | | Asteraceae
|
| HECR6 | Helianthus crenatus R.C. Jackson | Helianthus laciniatus | Asteraceae
|
| HECU7 | Helianthus cucumerifolius Torr. & Gray | Helianthus debilis ssp. cucumerifolius | Asteraceae
|
| HECU2 | Helianthus cusickii Gray | Cusick's sunflower | Asteraceae
|
| HEDA2 | Helianthus dalyi Britt. | Helianthus maximiliani | Asteraceae
|
| HEDEC2 | Helianthus debilis Nutt. ssp. cucumerifolius (Torr. & Gray) Heiser | cucumberleaf sunflower | Asteraceae
|
| HEDED | Helianthus debilis Nutt. ssp. debilis | cucumberleaf sunflower | Asteraceae
|
| HEDEH | Helianthus debilis Nutt. ssp. hirtus Heiser | Helianthus praecox ssp. hirtus | Asteraceae
|
| HEDEP | Helianthus debilis Nutt. ssp. praecox (Engelm. & Gray) Heiser | Helianthus praecox ssp. praecox | Asteraceae
|
| HEDER2 | Helianthus debilis Nutt. ssp. runyonii Heiser | Helianthus praecox ssp. runyonii | Asteraceae
|
| HEDES | Helianthus debilis Nutt. ssp. silvestris Heiser | cucumberleaf sunflower | Asteraceae
|
| HEDET | Helianthus debilis Nutt. ssp. tardiflorus Heiser | cucumberleaf sunflower | Asteraceae
|
| HEDEV | Helianthus debilis Nutt. ssp. vestitus (E.E. Wats.) Heiser | cucumberleaf sunflower | Asteraceae
|
| HEDEC3 | Helianthus debilis Nutt. var. cucumerifolius (Torr. & Gray) Gray | Helianthus debilis ssp. cucumerifolius | Asteraceae
|
| HEDES2 | Helianthus debilis Nutt. var. silvestris (Heiser) Cronq. | Helianthus debilis ssp. silvestris | Asteraceae
|
| HEDET2 | Helianthus debilis Nutt. var. tardiflorus (Heiser) Cronq. | Helianthus debilis ssp. tardiflorus | Asteraceae
|
| HEDEV2 | Helianthus debilis Nutt. var. vestitus (E.E. Wats.) Cronq. | Helianthus debilis ssp. vestitus | Asteraceae
|
| HEDE4 | Helianthus debilis Nutt. | cucumberleaf sunflower | Asteraceae
|
| HEDE | Helianthus decapetalus L. | thinleaf sunflower | Asteraceae
|
| HEDE9 | Helianthus dentatus Cav. | Viguiera dentata var. dentata | Asteraceae
|
| HEDE5 | Helianthus deserticola Heiser | Helianthus anomalus | Asteraceae
|
| HEDIA | Helianthus divaricatus L. var. angustifolius Kuntze | Helianthus divaricatus | Asteraceae
|
| HEDI2 | Helianthus divaricatus L. | woodland sunflower | Asteraceae
|
| HEDI5 | Helianthus �divariserratus R.W. Long | | Asteraceae
|
| HEDO | Helianthus �doronicoides Lam. (pro sp.) | | Asteraceae
|
| HEDO4 | Helianthus dowellianus M.A. Curtis | Helianthus occidentalis ssp. occidentalis | Asteraceae
|
| HEEG | Helianthus eggertii Small | Eggert's sunflower | Asteraceae
|
| HEEX | Helianthus exilis Gray | Helianthus bolanderi | Asteraceae
|
| HEFA6 | Helianthus fascicularis Greene | Helianthus nuttallii ssp. nuttallii | Asteraceae
|
| HEFI3 | Helianthus filiformis Small | Helianthus salicifolius | Asteraceae
|
| HEFL2 | Helianthus floridanus Gray ex Chapman | Florida sunflower | Asteraceae
|
| HEGIA | Helianthus giganteus L. ssp. alienus (E.E. Wats.) R.W. Long | Helianthus giganteus | Asteraceae
|
| HEGIS | Helianthus giganteus L. var. subtuberosus Britt. | Helianthus giganteus | Asteraceae
|
| HEGI | Helianthus giganteus L. | giant sunflower | Asteraceae
|
| HEGL2 | Helianthus glaucophyllus D.M. Sm. | whiteleaf sunflower | Asteraceae
|
| HEGL10 | Helianthus �glaucus Small (pro sp.) | | Asteraceae
|
| HEGR3 | Helianthus gracilentus Gray | slender sunflower | Asteraceae
|
| HEGRM | Helianthus grosseserratus Martens ssp. maximus R.W. Long | Helianthus grosseserratus | Asteraceae
|
| HEGRH | Helianthus grosseserratus Martens var. hypoleucus Gray | Helianthus grosseserratus | Asteraceae
|
| HEGR4 | Helianthus grosseserratus Martens | sawtooth sunflower | Asteraceae
|
| HEHE10 | Helianthus heiseri R.C. Jackson | Helianthus laciniatus | Asteraceae
|
| HEHE4 | Helianthus heterophyllus Nutt. | variableleaf sunflower | Asteraceae
|
| HEHIS | Helianthus hirsutus Raf. var. stenophyllus Torr. & Gray | Helianthus hirsutus | Asteraceae
|
| HEHIT | Helianthus hirsutus Raf. var. trachyphyllus Torr. & Gray | Helianthus hirsutus | Asteraceae
|
| HEHI2 | Helianthus hirsutus Raf. | hairy sunflower | Asteraceae
|
| HEIN9 | Helianthus instabilis E.E. Wats. | Helianthus grosseserratus | Asteraceae
|
| HEIN2 | Helianthus �intermedius R.W. Long | | Asteraceae
|
| HEKE2 | Helianthus �kellermanii Britt. (pro sp.) | | Asteraceae
|
| HELA8 | Helianthus laciniatus Gray | alkali sunflower | Asteraceae
|
| HELAR | Helianthus laetiflorus Pers. var. rigidus (Cass.) Fern. | Helianthus pauciflorus ssp. pauciflorus | Asteraceae
|
| HELAS | Helianthus laetiflorus Pers. var. subrhomboideus (Rydb.) Fern. | Helianthus pauciflorus ssp. subrhomboideus | Asteraceae
|
| HELA | Helianthus �laetiflorus Pers. (pro sp.) | cheerful sunflower | Asteraceae
|
| HELA2 | Helianthus laevigatus Torr. & Gray | smooth sunflower | Asteraceae
|
| HELA19 | Helianthus laevis L. | Bidens laevis | Asteraceae
|
| HELE5 | Helianthus lenticularis Dougl. ex Lindl. | Helianthus annuus | Asteraceae
|
| HELO3 | Helianthus longifolius Pursh | longleaf sunflower | Asteraceae
|
| HELU5 | Helianthus ludens Shinners | Viguiera phenax | Asteraceae
|
| HELU4 | Helianthus �luxurians E.E. Wats. (pro sp.) | | Asteraceae
|
| HEMA2 | Helianthus maximiliani Schrad. | Maximilian sunflower | Asteraceae
|
| HEMI3 | Helianthus microcephalus Torr. & Gray | small woodland sunflower | Asteraceae
|
| HEMOC | Helianthus mollis Lam. var. cordatus S. Wats. | Helianthus mollis | Asteraceae
|
| HEMO2 | Helianthus mollis Lam. | ashy sunflower | Asteraceae
|
| HEMO8 | Helianthus montanus E.E. Wats. | Helianthus strumosus | Asteraceae
|
| HEMU2 | Helianthus �multiflorus L. (pro sp.) | manyflower sunflower | Asteraceae
|