| Symbol | Scientific name | Common name/Accepted name (for synonyms) | Family |
| STAP | Sterculia apetala (Jacq.) Karst. | Panama tree | Sterculiaceae
|
| STFO2 | Sterculia foetida L. | hazel sterculia | Sterculiaceae
|
| STPL5 | Sterculia platanifolia L. f. | Firmiana simplex | Sterculiaceae
|
| STSE8 | Sterculia setigera Del. | sterculia | Sterculiaceae
|
| STTR7 | Sterculia tragacantha Lindley | sterculia | Sterculiaceae
|
| STUR2 | Sterculia urens Roxb. | sterculia | Sterculiaceae
|
| STERC | Sterculia L. | sterculia | Sterculiaceae
|
| STAL10 | Stereocaulon albicans Th. Fr. | Leprocaulon albicans | Uncertain Lichen Family
|
| STAL60 | Stereocaulon alpinum Laurer ex Funck | alpine snow lichen | Stereocaulaceae
|
| STAP4 | Stereocaulon apocalypticum Nyl. | snow lichen | Stereocaulaceae
|
| STAR13 | Stereocaulon arbuscula Nyl. | Leprocaulon arbuscula | Uncertain Lichen Family
|
| STAR60 | Stereocaulon arcticum Lynge | arctic snow lichen | Stereocaulaceae
|
| STAR12 | Stereocaulon arenarium (Savicz) Lamb | arenaria snow lichen | Stereocaulaceae
|
| STBO60 | Stereocaulon botryosum Ach. | snow lichen | Stereocaulaceae
|
| STCA29 | Stereocaulon capitellatum H. Magn. | snow lichen | Stereocaulaceae
|
| STCO17 | Stereocaulon condensatum Hoffm. | condensed snow lichen | Stereocaulaceae
|
| STCO60 | Stereocaulon coniophyllum Lamb | snow lichen | Stereocaulaceae
|
| STCO19 | Stereocaulon coralloides Fr. | Stereocaulon dactylophyllum | Stereocaulaceae
|
| STDAO | Stereocaulon dactylophyllum Florke var. occidentale (H. Magn.) Lamb | western snow lichen | Stereocaulaceae
|
| STDA60 | Stereocaulon dactylophyllum Florke | snow lichen | Stereocaulaceae
|
| STDE3 | Stereocaulon denudatum Florke | Stereocaulon vesuvianum | Stereocaulaceae
|
| STDE2 | Stereocaulon depreaultii Delise ex Nyl. | Depreault's snow lichen | Stereocaulaceae
|
| STEV | Stereocaulon evoutoides (H. Magn.) Frey | Stereocaulon saxatile | Stereocaulaceae
|
| STGL60 | Stereocaulon glareosum (Savicz) H. Magn. | glare snow lichen | Stereocaulaceae
|
| STGL5 | Stereocaulon glaucescens Tuck. | snow lichen | Stereocaulaceae
|
| STGR60 | Stereocaulon grande (H. Magn.) H. Magn. | grand snow lichen | Stereocaulaceae
|
| STGR8 | Stereocaulon groenlandicum (E. Dahl) Lamb | Greenland snow lichen | Stereocaulaceae
|
| STIN60 | Stereocaulon incrustatum Florke | snow lichen | Stereocaulaceae
|
| STIN61 | Stereocaulon intermedium (Savicz) H. Magn. | intermediate snow lichen | Stereocaulaceae
|
| STLE10 | Stereocaulon leprocephalum Vainio | snow lichen | Stereocaulaceae
|
| STMI8 | Stereocaulon microcarpum Mull. Arg. | snow lichen | Stereocaulaceae
|
| STMI10 | Stereocaulon microscopicum (Vill.) Frey | Leprocaulon microscopicum | Uncertain Lichen Family
|
| STMY60 | Stereocaulon myriocarpum Th. Fr. | snow lichen | Stereocaulaceae
|
| STNA | Stereocaulon nanodes Tuck. | snow lichen | Stereocaulaceae
|
| STOC4 | Stereocaulon octomerum Mull. Arg. | snow lichen | Stereocaulaceae
|
| STPA60 | Stereocaulon paschale (L.) Hoffm. | snow lichen | Stereocaulaceae
|
| STPI7 | Stereocaulon pileatum Ach. | snow lichen | Stereocaulaceae
|
| STPS3 | Stereocaulon pseudoarbuscula Asah. | Leprocaulon subalbicans | Uncertain Lichen Family
|
| STQU2 | Stereocaulon quisquilare (Leers) Hoffm. | Leprocaulon microscopicum | Uncertain Lichen Family
|
| STRI60 | Stereocaulon rivulorum H. Magn. | snow lichen | Stereocaulaceae
|
| STSAS2 | Stereocaulon sasakii Zalhlbr. var. simplex (Riddle) Lamb | Sasak's snow lichen | Stereocaulaceae
|
| STSAT | Stereocaulon sasakii Zahlbr. var. tomentosoides Lamb | tomentose snow lichen | Stereocaulaceae
|
| STSA9 | Stereocaulon sasakii Zahlbr. | Sasak's snow lichen | Stereocaulaceae
|
| STSA6 | Stereocaulon saviczii Du Rietz | Savicz's snow lichen | Stereocaulaceae
|
| STSA60 | Stereocaulon saxatile H. Magn. | snow lichen | Stereocaulaceae
|
| STSP60 | Stereocaulon spathuliferum Vainio | snow lichen | Stereocaulaceae
|
| STST10 | Stereocaulon sterile (Savicz) Lamb ex Krog | snow lichen | Stereocaulaceae
|
| STSU5 | Stereocaulon subalbicans Lamb | Leprocaulon subalbicans | Uncertain Lichen Family
|
| STSU61 | Stereocaulon subcoralloides (Nyl.) Nyl. | snow lichen | Stereocaulaceae
|
| STSY60 | Stereocaulon symphycheilum Lamb | snow lichen | Stereocaulaceae
|
| STTE12 | Stereocaulon tennesseense H. Magn. ex Degel. | Tennessee snow lichen | Stereocaulaceae
|
| STTO60 | Stereocaulon tomentosum Fr. | tomentose snow lichen | Stereocaulaceae
|
| STVE60 | Stereocaulon vesuvianum Pers. | Vesuvius snow lichen | Stereocaulaceae
|
| STERE2 | Stereocaulon Hoffm. | snow lichen | Stereocaulaceae
|
| STDO2 | Stereophyllum donnellii (Aust.) Card. ex Par. | Entodontopsis leucostega | Stereophyllaceae
|
| STLE11 | Stereophyllum leucostegum (Brid.) Mitt. | Entodontopsis leucostega | Stereophyllaceae
|
| STRA3 | Stereophyllum radiculosum (Hook.) Mitt. | stereophyllum moss | Stereophyllaceae
|
| STWR5 | Stereophyllum wrightii (Sull.) Ren. & Card. | Stereophyllum radiculosum | Stereophyllaceae
|
| STERE3 | Stereophyllum Mitt. | stereophyllum moss | Stereophyllaceae
|
| STLU4 | Sternbergia lutea (L.) Ker-Gawl. ex Spreng. | winter daffodil | Liliaceae
|
| STERN | Sternbergia Waldst. & Kit. | winter daffodil | Liliaceae
|
| STCO13 | Stethoma comata (L.) Britt. | Justicia comata | Acanthaceae
|
| STPE4 | Stethoma pectoralis (Jacq.) Raf. | Justicia pectoralis | Acanthaceae
|
| STVE3 | Stethoma verticillaris (Nees) Britt. | Justicia martinsoniana | Acanthaceae
|
| STLE | Stevia lemmonii (Gray) Gray | Lemmon's candyleaf | Asteraceae
|
| STMI | Stevia micrantha Lag. | annual candyleaf | Asteraceae
|
| STOVT | Stevia ovata Willd. var. texana Grashoff | Texan candyleaf | Asteraceae
|
| STOV3 | Stevia ovata Willd. | roundleaf candyleaf | Asteraceae
|
| STPLA | Stevia plummerae Gray var. alba Gray | Plummer's candyleaf | Asteraceae
|
| STPLP | Stevia plummerae Gray var. plummerae | Plummer's candyleaf | Asteraceae
|
| STPL | Stevia plummerae Gray | Plummer's candyleaf | Asteraceae
|
| STRE2 | Stevia rebaudiana (Bertoni) Bertoni | candyleaf | Asteraceae
|
| STRH2 | Stevia rhombifolia Kunth | Stevia ovata var. texana | Asteraceae
|
| STSAS | Stevia salicifolia Cav. var. stenophylla (Gray) B.L. Robins. | Stevia salicifolia | Asteraceae
|
| STSA | Stevia salicifolia Cav. | willowleaf candyleaf | Asteraceae
|
| STSEH3 | Stevia serrata Cav. var. haplopappa B.L. Robins. | Stevia serrata | Asteraceae
|
| STSEI | Stevia serrata Cav. var. ivifolia (Willd.) B.L. Robins. | Stevia serrata | Asteraceae
|
| STSE2 | Stevia serrata Cav. | sawtooth candyleaf | Asteraceae
|
| STST9 | Stevia stenophylla Gray | Stevia salicifolia | Asteraceae
|
| STVI3 | Stevia viscida Kunth | viscid candyleaf | Asteraceae
|
| STEVI | Stevia Cav. | candyleaf | Asteraceae
|
| STMA | Stewartia malacodendron L. | silky camellia | Theaceae
|
| STOV | Stewartia ovata (Cav.) Weatherby | mountain camellia | Theaceae
|
| STPE7 | Stewartia pentagyna L'H�r. | Stewartia ovata | Theaceae
|
| STEWA | Stewartia L. | stewartia | Theaceae
|
| STBI5 | Sticherus bifidus (Willd.) Ching | Mexican umbrella fern | Gleicheniaceae
|
| STBR5 | Sticherus brevipubis (Christ) A.R. Sm. | clothed umbrella fern | Gleicheniaceae
|
| STOW | Sticherus owhyensis (Hook.) Ching | Hawai'i umbrella fern | Gleicheniaceae
|
| STICH | Sticherus K. Presl | umbrella fern | Gleicheniaceae
|
| STAN8 | Sticta anthraspis Ach. | Pseudocyphellaria anthraspis | Lobariaceae
|
| STAR61 | Sticta arctica Degel. | arctic spotted felt lichen | Lobariaceae
|
| STAU2 | Sticta aurata Ach. | Pseudocyphellaria aurata | Lobariaceae
|
| STBE2 | Sticta beauvoisii Delise | Beauvois' spotted felt lichen | Lobariaceae
|
| STCA30 | Sticta canariensis (Bory) Bory ex Delise | spotted felt lichen | Lobariaceae
|
| STCR9 | Sticta crocata (L.) Ach. | Pseudocyphellaria crocata | Lobariaceae
|
| STER | Sticta erosa (Eschw.) Tuck. | Lobaria ravenelii | Lobariaceae
|
| STFU60 | Sticta fuliginosa (Hoffm.) Ach. | spotted felt lichen | Lobariaceae
|
| STHA5 | Sticta hallii Tuck. | Lobaria hallii | Lobariaceae
|
| STLI60 | Sticta limbata (Sm.) Ach. | spotted felt lichen | Lobariaceae
|
| STLI9 | Sticta linita Ach. | Lobaria linita | Lobariaceae
|
| STOR4 | Sticta oregana Tuck. | Lobaria oregana | Lobariaceae
|