| Symbol | Scientific name | Common name/Accepted name (for synonyms) | Family |
| TOCA3 | Tomasellia californica (Zahlbr.) R. C. Harris | Mycoporum californicum | Mycoporaceae
|
| TODI3 | Tomasellia difforme (Minks) | | Arthopyreniaceae
|
| TOES | Tomasellia eschweileri (Mull. Arg.) R. C. Harris | Mycoporum eschweileri | Mycoporaceae
|
| TOLA3 | Tomasellia lactea (Ach.) R. C. Harris | Mycoporum lacteum | Mycoporaceae
|
| TOMA3 | Tomasellia macularis (Minks ex Willey) R. C. Harris | | Arthopyreniaceae
|
| TOSP2 | Tomasellia sparsella (Nyl.) R. C. Harris | Mycoporum sparsellum | Mycoporaceae
|
| TOMAS | Tomasellia A. Massal. | tomasellia | Arthopyreniaceae
|
| TOMEN | Tomenthypnum Loeske | tomenthypnum | Brachytheciaceae
|
| TOFA | Tomentypnum falcifolium (Ren. ex Nichols) Tuom. in Ahti & Fagers. | sickleleaf tomentypnum moss | Brachytheciaceae
|
| TONIF | Tomentypnum nitens (Hedw.) Loeske var. falcifolium Ren. ex Nichols | Tomentypnum falcifolium | Brachytheciaceae
|
| TONII | Tomentypnum nitens (Hedw.) Loeske var. insigne (Milde) C. Jens. | Tomentypnum nitens | Brachytheciaceae
|
| TONII2 | Tomentypnum nitens (Hedw.) Loeske var. involutum (Limpr.) C. Jens. | Tomentypnum nitens | Brachytheciaceae
|
| TONI70 | Tomentypnum nitens (Hedw.) Loeske | tomentypnum moss | Brachytheciaceae
|
| TOPA10 | Tomentypnum paulianum (Grout) Broth. ex Robins. | Sanionia uncinata var. uncinata | Amblystegiaceae
|
| TOMEN2 | Tomentypnum Loeske | tomentypnum moss | Brachytheciaceae
|
| TOFL | Tonella floribunda Gray | manyflower tonella | Scrophulariaceae
|
| TOTE | Tonella tenella (Benth.) Heller | lesser baby innocence | Scrophulariaceae
|
| TONEL | Tonella Nutt. ex Gray | tonella | Scrophulariaceae
|
| TOAB | Tonestus aberrans (A. Nels.) Nesom & D. Morgan | Idaho goldenweed | Asteraceae
|
| TOAL2 | Tonestus alpinus (L.C. Anders. & Goodrich) Nesom & D. Morgan | alpine serpentweed | Asteraceae
|
| TOEX3 | Tonestus eximius (Hall) A. Nels. & J.F. Macbr. | Lake Tahoe serpentweed | Asteraceae
|
| TOGR2 | Tonestus graniticus (Tiehm & L. Shultz) Nesom & D. Morgan | granite serpentweed | Asteraceae
|
| TOKIB | Tonestus kingii (D.C. Eat.) Nesom var. barnebyana (Welsh & Goodrich) Nesom | Barneby's serpentweed | Asteraceae
|
| TOKIK | Tonestus kingii (D.C. Eat.) Nesom var. kingii | King's serpentweed | Asteraceae
|
| TOKI | Tonestus kingii (D.C. Eat.) Nesom | King's serpentweed | Asteraceae
|
| TOLY | Tonestus lyallii (Gray) A. Nels. | Lyall's goldenweed | Asteraceae
|
| TOMI | Tonestus microcephalus (Cronq.) Nesom & D. Morgan | smallhead heathgoldenrod | Asteraceae
|
| TOPE | Tonestus peirsonii (Keck) Nesom & D. Morgan | Peirson's serpentweed | Asteraceae
|
| TOPY | Tonestus pygmaeus (Torr. & Gray) A. Nels. | pygmy goldenweed | Asteraceae
|
| TONES | Tonestus A. Nels. | serpentweed | Asteraceae
|
| TOAL3 | Toninia alutacea (Anzi) Jatta | bruised lichen | Catillariaceae
|
| TOAR6 | Toninia arctica Timdal | bruised lichen | Catillariaceae
|
| TOAR5 | Toninia aromatica (Sm.) A. Massal. | aromatic bruised lichen | Catillariaceae
|
| TOAT | Toninia athallina (Hepp) Timdal | bruised lichen | Catillariaceae
|
| TOBU | Toninia bullata (G. Meyen & Flotow) Zahlbr. | bruised lichen | Catillariaceae
|
| TOCA4 | Toninia caeruleonigricans auct. | Toninia sedifolia | Catillariaceae
|
| TOCA5 | Toninia candida (Weber) Th. Fr. | bruised lichen | Catillariaceae
|
| TOCA6 | Toninia caulescens Anzi | Toninia squalida | Catillariaceae
|
| TOCI2 | Toninia cinereovirens (Schaerer) A. Massal. | bruised lichen | Catillariaceae
|
| TOCO4 | Toninia conglomerata (Ach.) Boistel | Psorinia conglomerata | Lecanoraceae
|
| TOKO | Toninia kolax Poelt | Toninia verrucarioides | Catillariaceae
|
| TOLO3 | Toninia lobulata (Sommerf.) Lynge | Mycobilimbia lobulata | Porpidiaceae
|
| TOLU | Toninia lutosa (Ach.) Timdal | bruised lichen | Catillariaceae
|
| TOMA2 | Toninia massata (Tuck.) Herre | bruised lichen | Catillariaceae
|
| TOOP | Toninia opuntioides (Vill.) Timdal | bruised lichen | Catillariaceae
|
| TOPE3 | Toninia pennina (Schaerer) Gyelnik | bruised lichen | Catillariaceae
|
| TOPH | Toninia philippea (Mont.) Timdal | bruised lichen | Catillariaceae
|
| TOPH2 | Toninia physaroides (Opiz) Zahlbr. | bruised lichen | Catillariaceae
|
| TORUP | Toninia ruginosa (Tuck.) Herre ssp. pacifica Timdal | bruised lichen | Catillariaceae
|
| TORUR | Toninia ruginosa (Tuck.) Herre ssp. ruginosa | bruised lichen | Catillariaceae
|
| TORU | Toninia ruginosa (Tuck.) Herre | bruised lichen | Catillariaceae
|
| TOSC5 | Toninia sculpturata (H. Magn.) Timdal | bruised lichen | Catillariaceae
|
| TOSE2 | Toninia sedifolia (Scop.) Timdal | bruised lichen | Catillariaceae
|
| TOSQ | Toninia squalida (Ach.) A. Massal. | squalid bruised lichen | Catillariaceae
|
| TOSQ2 | Toninia squarrosa (Ach.) Th. Fr. | Toninia squalida | Catillariaceae
|
| TOSU3 | Toninia subdiffracta Timdal | bruised lichen | Catillariaceae
|
| TOSU4 | Toninia submexicana de Lesd. | bruised lichen | Catillariaceae
|
| TOSU5 | Toninia superioris Timdal | bruised lichen | Catillariaceae
|
| TOTA2 | Toninia tabacina auct. | Toninia tristis | Catillariaceae
|
| TOTA3 | Toninia talparum Timdal | bruised lichen | Catillariaceae
|
| TOTRA | Toninia tristis (Th. Fr.) Th. Fr. ssp. arizonica Timdal | bruised lichen | Catillariaceae
|
| TOTRA2 | Toninia tristis (Th. Fr.) Th. Fr. ssp. asiae-centralis (H. Magn.) Timdal | bruised lichen | Catillariaceae
|
| TOTRC | Toninia tristis (Th. Fr.) Th. Fr. ssp. canadensis Timdal | bruised lichen | Catillariaceae
|
| TOTRS | Toninia tristis (Th. Fr.) Th. Fr. ssp. scholanderi (Lynge) Timdal | bruised lichen | Catillariaceae
|
| TOTRT | Toninia tristis (Th. Fr.) Th. Fr. ssp. tristis | bruised lichen | Catillariaceae
|
| TOTR2 | Toninia tristis (Th. Fr.) Th. Fr. | bruised lichen | Catillariaceae
|
| TOVE5 | Toninia verrucarioides (Nyl.) Timdal | bruised lichen | Catillariaceae
|
| TOWE | Toninia weberi Timdal | bruised lichen | Catillariaceae
|
| TONIN | Toninia A. Massal. | bruised lichen | Catillariaceae
|
| TOHE2 | Tontanea herbacea (P. Br.) Standl. | Coccocypselum herbaceum | Rubiaceae
|
| TOAU2 | Toona australis (F. Muell.) Harms | Toona ciliata ssp. ciliata var. australis | Meliaceae
|
| TOCIA | Toona ciliata Roemer ssp. ciliata var. australis (F. Muell.) Bahadur | Australian redcedar | Meliaceae
|
| TOCIC | Toona ciliata Roemer ssp. ciliata | Australian redcedar | Meliaceae
|
| TOCI | Toona ciliata Roemer | Australian redcedar | Meliaceae
|
| TOONA | Toona (Endl.) Roemer | redcedar | Meliaceae
|
| TOAP3 | Topelia aperiens P. M. Jorg. & Vezda | | Stictidaceae
|
| TOCA7 | Topelia californica P. M. Jorg. & Vezda | | Stictidaceae
|
| TOPEL | Topelia P. M. Jorg. & Vezda | topelia | Stictidaceae
|
| TOAP2 | Tordylium apulum L. | Mediterranean hartwort | Apiaceae
|
| TORDY | Tordylium L. | tordylium | Apiaceae
|
| TOAS | Torenia asiatica L. | wishbone flower | Scrophulariaceae
|
| TOCR | Torenia crustacea (L.) Cham. & Schlecht. | Lindernia crustacea | Scrophulariaceae
|
| TOFO2 | Torenia fournieri Linden ex E. Fourn. | bluewings | Scrophulariaceae
|
| TOREN | Torenia L. | torenia | Scrophulariaceae
|
| TOARA | Torilis arvensis (Huds.) Link ssp. arvensis | spreading hedgeparsley | Apiaceae
|
| TOARP | Torilis arvensis (Huds.) Link ssp. purpurea (Ten.) Hayek | spreading hedgeparsley | Apiaceae
|
| TOAR | Torilis arvensis (Huds.) Link | spreading hedgeparsley | Apiaceae
|
| TOHE | Torilis heterophylla Guss | Torilis arvensis ssp. purpurea | Apiaceae
|
| TOJA | Torilis japonica (Houtt.) DC. | erect hedgeparsley | Apiaceae
|
| TOLE2 | Torilis leptophylla (L.) Reichenb. f. | bristlefruit hedgeparsley | Apiaceae
|
| TONO | Torilis nodosa (L.) Gaertn. | knotted hedgeparsley | Apiaceae
|
| TOPU3 | Torilis purpurea (Ten.) Guss | Torilis arvensis ssp. purpurea | Apiaceae
|
| TOSC2 | Torilis scabra (Thunb.) DC. | rough hedgeparsley | Apiaceae
|
| TORIL | Torilis Adans. | hedgeparsley | Apiaceae
|
| TOEP | Tornabea ephebea (Ach.) Kurok. | Tornabea scutellifera | Physciaceae
|
| TOSC6 | Tornabea scutellifera (With.) J. R. Laundon | | Physciaceae
|
| TORNA | Tornabea Osthagen | tornabea | Physciaceae
|
| TOCU | Torralbasia cuneifolia (C. Wright) Krug & Urban | boje | Celastraceae
|
| TORRA | Torralbasia Krug & Urban | torralbasia | Celastraceae
|
| TOOD2 | Torresia odorata (L.) A.S. Hitchc. | Hierochloe odorata | Poaceae
|
| TOCA | Torreya californica Torr. | California nutmeg | Taxaceae
|