| Symbol | Scientific name | Common name/Accepted name (for synonyms) | Family |
| HYOC4 | Hypogymnia oceanica Goward | seaside tube lichen | Parmeliaceae
|
| HYOR2 | Hypogymnia oroarctica Krog | Brodoa oroarctica | Parmeliaceae
|
| HYPH60 | Hypogymnia physodes (L.) Nyl. | tube lichen | Parmeliaceae
|
| HYPS60 | Hypogymnia pseudophysodes (Asah.) Rass. | Hypogymnia oceanica | Parmeliaceae
|
| HYPU6 | Hypogymnia pulverata (Nyl. ex Crombie) Elix | tube lichen | Parmeliaceae
|
| HYRU3 | Hypogymnia rugosa (G. Merr.) L. Pike | tube lichen | Parmeliaceae
|
| HYSU5 | Hypogymnia subcapitata (Nyl.) Rass. | tube lichen | Parmeliaceae
|
| HYSU60 | Hypogymnia subobscura (Vainio) Poelt | tube lichen | Parmeliaceae
|
| HYSU10 | Hypogymnia subphysodes (Krempelh.) Filson | tube lichen | Parmeliaceae
|
| HYTU60 | Hypogymnia tubulosa (Schaerer) Hav. | tube lichen | Parmeliaceae
|
| HYVI60 | Hypogymnia vittata (Ach.) Parrique | Vitt tube lichen | Parmeliaceae
|
| HYPOG2 | Hypogymnia (Nyl.) Nyl. | tube lichen | Parmeliaceae
|
| HYVI3 | Hypogynium virgatum (Desv.) Dandy | West Indian bluestem | Poaceae
|
| HYPOG | Hypogynium Nees | West Indian bluestem | Poaceae
|
| HYNI2 | Hypolepis nigrescens Hook. | black beadfern | Dennstaedtiaceae
|
| HYPU2 | Hypolepis punctata (Thunb.) Mett. | dotted beadfern | Dennstaedtiaceae
|
| HYRE2 | Hypolepis repens (L.) K. Presl | bramblefern | Dennstaedtiaceae
|
| HYTE3 | Hypolepis tenerrima Maxon | royal beadfern | Dennstaedtiaceae
|
| HYUR | Hypolepis urbanii Brause | ponce beadfern | Dennstaedtiaceae
|
| HYPOL | Hypolepis Bernh. | beadfern | Dennstaedtiaceae
|
| HYBE | Hypolytrum berteroi Spreng. | Rhynchospora berteroi | Cyperaceae
|
| HYDI5 | Hypolytrum dissitiflorum Steud. | | Cyperaceae
|
| HYPOL2 | Hypolytrum Pers. | | Cyperaceae
|
| HYAM5 | Hypopitys americana (DC.) Small | Monotropa hypopithys | Monotropaceae
|
| HYFI2 | Hypopitys fimbriata (Gray) T.J. Howell | Monotropa hypopithys | Monotropaceae
|
| HYIN | Hypopitys insignata Bickn. | Monotropa hypopithys | Monotropaceae
|
| HYLA9 | Hypopitys lanuginosa (Michx.) Nutt. | Monotropa hypopithys | Monotropaceae
|
| HYLA10 | Hypopitys latisquama Rydb. | Monotropa hypopithys | Monotropaceae
|
| HYMO3 | Hypopitys monotropa Crantz | Monotropa hypopithys | Monotropaceae
|
| HYFA4 | Hypopterygium fauriei Besch. | Faurie's hypopterygium moss | Hypopterygiaceae
|
| HYTA2 | Hypopterygium tamariscinum (Hedw.) Brid. | hypopterygium moss | Hypopterygiaceae
|
| HYPOP3 | Hypopterygium Brid. | hypopterygium moss | Hypopterygiaceae
|
| HYCO16 | Hypotrachyna costaricensis (Nyl.) Hale | | Parmeliaceae
|
| HYCR5 | Hypotrachyna croceopustulata (Kurok.) Hale | | Parmeliaceae
|
| HYDE8 | Hypotrachyna densirhizinata (Kurok.) Hale | | Parmeliaceae
|
| HYDE60 | Hypotrachyna dentella (Hale & Kurok.) Hale | | Parmeliaceae
|
| HYEN2 | Hypotrachyna ensifolia (Kurok.) Hale | | Parmeliaceae
|
| HYFO3 | Hypotrachyna formosana (Zahlbr.) Hale | Hypotrachyna osseoalba | Parmeliaceae
|
| HYGO | Hypotrachyna gondylophora (Hale) Hale | | Parmeliaceae
|
| HYIM2 | Hypotrachyna imbricatula (Zahlbr.) Hale | | Parmeliaceae
|
| HYLA13 | Hypotrachyna laevigata (Sm.) Hale | | Parmeliaceae
|
| HYLI5 | Hypotrachyna livida (Taylor) Hale | | Parmeliaceae
|
| HYOO | Hypotrachyna oostingii (J. P. Dey) Hale | | Parmeliaceae
|
| HYOS | Hypotrachyna osseoalba (Vainio) Park & Hale | | Parmeliaceae
|
| HYPO6 | Hypotrachyna polydactyla (Krog & Swinscow) T. Nash | | Parmeliaceae
|
| HYPR5 | Hypotrachyna producta Hale | | Parmeliaceae
|
| HYPR6 | Hypotrachyna prolongata (Kurok.) Hale | | Parmeliaceae
|
| HYPS2 | Hypotrachyna pseudosinuosa (Asah.) Hale | | Parmeliaceae
|
| HYPU7 | Hypotrachyna pulvinata (Fee) Hale | | Parmeliaceae
|
| HYPU8 | Hypotrachyna pustulifera (Hale) Skorepa | | Parmeliaceae
|
| HYRA7 | Hypotrachyna rachista (Hale) Hale | Hypotrachyna prolongata | Parmeliaceae
|
| HYRE4 | Hypotrachyna revoluta (Florke) Hale | | Parmeliaceae
|
| HYRO6 | Hypotrachyna rockii (Zahlbr.) Hale | | Parmeliaceae
|
| HYSH | Hypotrachyna showmanii Hale | | Parmeliaceae
|
| HYSI60 | Hypotrachyna sinuosa (Sm.) Hale | | Parmeliaceae
|
| HYSU6 | Hypotrachyna subsaxatilis (de Lesd.) Hale | | Parmeliaceae
|
| HYTA4 | Hypotrachyna taylorensis (M. E. Mitch.) Hale | | Parmeliaceae
|
| HYTH | Hypotrachyna thysanota (Kurok.) Hale | | Parmeliaceae
|
| HYVI7 | Hypotrachyna virginica (Hale) Hale | | Parmeliaceae
|
| HYPOT2 | Hypotrachyna (Vainio) Hale | hypotrachyna | Parmeliaceae
|
| HYCU5 | Hypoxis curtissii Rose | Curtis' star-grass | Liliaceae
|
| HYDE3 | Hypoxis decumbens L. | Hypoxis hirsuta | Liliaceae
|
| HYHIL | Hypoxis hirsuta (L.) Coville var. leptocarpa (Engelm. & Gray) Brackett | Hypoxis curtissii | Liliaceae
|
| HYHI2 | Hypoxis hirsuta (L.) Coville | common goldstar | Liliaceae
|
| HYJU | Hypoxis juncea Sm. | fringed yellow star-grass | Liliaceae
|
| HYKI2 | Hypoxis kilimanjarica Baker | star-grass | Liliaceae
|
| HYLE2 | Hypoxis leptocarpa (Engelm. & Gray) Small | Hypoxis curtissii | Liliaceae
|
| HYLO3 | Hypoxis longii Fern. | Hypoxis sessilis | Liliaceae
|
| HYME2 | Hypoxis mexicana J.A. & J.H. Schultes | Mexican yellow star-grass | Liliaceae
|
| HYMI2 | Hypoxis micrantha Pollard | Hypoxis wrightii | Liliaceae
|
| HYRI2 | Hypoxis rigida Chapman | stiff star-grass | Liliaceae
|
| HYSE2 | Hypoxis sessilis L. | glossyseed yellow star-grass | Liliaceae
|
| HYWR3 | Hypoxis wrightii (Baker) Brackett | Wright's star-grass | Liliaceae
|
| HYPOX | Hypoxis L. | star-grass | Liliaceae
|
| HYALS | Hyptis alata (Raf.) Shinners var. stenophylla Shinners | Hyptis alata | Lamiaceae
|
| HYAL | Hyptis alata (Raf.) Shinners | clustered bushmint | Lamiaceae
|
| HYAM7 | Hyptis americana (Aubl.) Urban | Hyptis spicigera | Lamiaceae
|
| HYAM3 | Hyptis americana (Poit.) Briq. | American bushmint | Lamiaceae
|
| HYAT2 | Hyptis atrorubens Poit. | marubio oscuro | Lamiaceae
|
| HYCA12 | Hyptis capitata Jacq. | false ironwort | Lamiaceae
|
| HYEM | Hyptis emoryi Torr. | desert lavender | Lamiaceae
|
| HYES | Hyptis escobilla Urban | bayamon | Lamiaceae
|
| HYLA6 | Hyptis lantanifolia Poit. | island bushmint | Lamiaceae
|
| HYMUS | Hyptis mutabilis (A. Rich.) Briq. var. spicata (Poit.) Briq. | Hyptis mutabilis | Lamiaceae
|
| HYMU2 | Hyptis mutabilis (A. Rich.) Briq. | tropical bushmint | Lamiaceae
|
| HYPE3 | Hyptis pectinata (L.) Poit. | comb bushmint | Lamiaceae
|
| HYRA5 | Hyptis radiata Willd. | Hyptis alata | Lamiaceae
|
| HYSC4 | Hyptis scoparia Poit. | Hyptis americana | Lamiaceae
|
| HYSP4 | Hyptis spicigera Lam. | marubio | Lamiaceae
|
| HYSU3 | Hyptis suaveolens (L.) Poit. | pignut | Lamiaceae
|
| HYVE4 | Hyptis verticillata Jacq. | John Charles | Lamiaceae
|
| HYPTI | Hyptis Jacq. | bushmint | Lamiaceae
|
| HYOF | Hyssopus officinalis L. | hyssop | Lamiaceae
|
| HYSSO | Hyssopus L. | hyssopus | Lamiaceae
|
| HYCA8 | Hystrix californica Boland. ex Thurb. | Elymus californicus | Poaceae
|
| HYHY2 | Hystrix hystrix (L.) Millsp. | Elymus hystrix var. hystrix | Poaceae
|
| HYPAB | Hystrix patula Moench var. bigeloviana (Fern.) Deam | Elymus hystrix var. bigeloviana | Poaceae
|
| HYPA3 | Hystrix patula Moench | Elymus hystrix var. hystrix | Poaceae
|
| IBMA | Ibatia maritima (Jacq.) Dcne. | Matelea maritima | Asclepiadaceae
|
| IBAM | Iberis amara L. | annual candytuft | Brassicaceae
|
| IBCA | Iberis candicans Raf. | Dimorphocarpa candicans | Brassicaceae
|