| Symbol | Scientific name | Common name/Accepted name (for synonyms) | Family |
| STEL5 | Strigula elegans (Fee) Mull. Arg. | Strigula smaragdula | Strigulaceae
|
| STGR15 | Strigula griseonitens R. C. Harris | | Strigulaceae
|
| STHY10 | Strigula hypothallina R. C. Harris | | Strigulaceae
|
| STJA4 | Strigula jamesii (Swinscow) R. C. Harris | | Strigulaceae
|
| STLA19 | Strigula laceribracae R. C. Harris | | Strigulaceae
|
| STNI3 | Strigula nitidula Mont. | | Strigulaceae
|
| STPH | Strigula phaea (Ach.) R. C. Harris | | Strigulaceae
|
| STSM | Strigula smaragdula Fr.:Fr. | | Strigulaceae
|
| STST11 | Strigula stigmatella (Ach.) R. C. Harris | | Strigulaceae
|
| STSU8 | Strigula subelegans Vainio | | Strigulaceae
|
| STSU4 | Strigula submuriformis (R. C. Harris) R. C. Harris | | Strigulaceae
|
| STSY5 | Strigula sychnogonioides (Nitschke) R. C. Harris | | Strigulaceae
|
| STVI13 | Strigula viridiseda (Nyl.) R. C. Harris | | Strigulaceae
|
| STWI2 | Strigula wilsonii (Riddle) R. C. Harris | | Strigulaceae
|
| STRIG2 | Strigula Fr. | strigula | Strigulaceae
|
| STST6 | Strobus strobus (L.) Small | Pinus strobus | Pinaceae
|
| STTI2 | Stroganowia tiehmii Rollins | Talapoosa Peak pearpod | Brassicaceae
|
| STROG | Stroganowia Kar. & Kir. | stroganowia | Brassicaceae
|
| STRU4 | Strongylodon ruber Vogel | Hawai'i jadevine | Fabaceae
|
| STRON | Strongylodon Vogel | strongylodon | Fabaceae
|
| STEM4 | Strophanthus eminii Asch. & Pax ex Pax | Emin's strophanthus | Apocynaceae
|
| STGR11 | Strophanthus gratus (Wallich & Hook. ex Benth.) Baillon | ouabain | Apocynaceae
|
| STHI5 | Strophanthus hispidus A. DC. | hispid strophanthus | Apocynaceae
|
| STKO | Strophanthus kombe Oliver | Kombe arrow poison | Apocynaceae
|
| STPR6 | Strophanthus preussii Engler & Pax ex Pax | Preuss' strophanthus | Apocynaceae
|
| STSA7 | Strophanthus sarmentosus DC. | strophanthus | Apocynaceae
|
| STTH4 | Strophanthus thollonii Franchet | Thollon's strophanthus | Apocynaceae
|
| STROP4 | Strophanthus DC. | strophanthus | Apocynaceae
|
| STAR7 | Strophocaulos arvensis (L.) Small | Convolvulus arvensis | Convolvulaceae
|
| STHEM | Strophostyles helvula (L.) Ell. var. missouriensis (S. Wats.) Britt. | Strophostyles helvula | Fabaceae
|
| STHE4 | Strophostyles helvula (L.) Ell. | trailing fuzzybean | Fabaceae
|
| STLE6 | Strophostyles leiosperma (Torr. & Gray) Piper | slickseed fuzzybean | Fabaceae
|
| STPA15 | Strophostyles pauciflora (Benth.) S. Wats. | Strophostyles leiosperma | Fabaceae
|
| STUMP | Strophostyles umbellata (Muhl. ex Willd.) Britt. var. paludigena Fern. | Strophostyles umbellata | Fabaceae
|
| STUM2 | Strophostyles umbellata (Muhl. ex Willd.) Britt. | pink fuzzybean | Fabaceae
|
| STROP | Strophostyles Ell. | fuzzybean | Fabaceae
|
| STSP7 | Struchium sparganophorum (L.) Kuntze | yerba de faja | Asteraceae
|
| STRUC | Struchium P. Br. | struchium | Asteraceae
|
| STMA4 | Strumpfia maritima Jacq. | pride of Big Pine | Rubiaceae
|
| STRUM | Strumpfia Jacq. | strumpfia | Rubiaceae
|
| STEX2 | Struthiopteris exaltata (F�e) Broadh. | Blechnum divergens | Blechnaceae
|
| STLI5 | Struthiopteris lineata (Sw.) Broadh. | Blechnum lineatum | Blechnaceae
|
| STPO5 | Struthiopteris polypodioides (Sw.) Trev. | Blechnum fragile | Blechnaceae
|
| STSP9 | Struthiopteris spicant (L.) Weiss | Blechnum spicant | Blechnaceae
|
| STNU4 | Strychnos nux-vomica L. | strychnine tree | Loganiaceae
|
| STSP8 | Strychnos spinosa Lam. | Natal orange | Loganiaceae
|
| STTO6 | Strychnos toxifera Schomb. ex Benth. | strychnine | Loganiaceae
|
| STRYC | Strychnos L. | strychnos | Loganiaceae
|
| STAD | Stryphnodendron adstringens (C. Martius) Cov. | stryphnodendron | Fabaceae
|
| STBA6 | Stryphnodendron barbadetimam (Vell. Conc.) C. Martius | stryphnodendron | Fabaceae
|
| STRYP | Stryphnodendron C. Martius | stryphnodendron | Fabaceae
|
| STFIA | Stuckenia filiformis (Pers) Boerner ssp. alpinus (Blytt) Haynes, D.H. Les, & M. Kral | fineleaf pondweed | Potamogetonaceae
|
| STFIF | Stuckenia filiformis (Pers) Boerner ssp. filiformis | fineleaf pondweed | Potamogetonaceae
|
| STFIO | Stuckenia filiformis (Pers) Boerner ssp. occidentalis (J.W. Robbins) Haynes, D.H. Les, & M. Kral | western fineleaf pondweed | Potamogetonaceae
|
| STFI6 | Stuckenia filiformis (Pers) Boerner | fineleaf pondweed | Potamogetonaceae
|
| STPE12 | Stuckenia pectinatus (L.) Boerner | sago pondweed | Potamogetonaceae
|
| STST18 | Stuckenia striatus (Ruiz & Pav�n) Holub | broadleaf pondweed | Potamogetonaceae
|
| STVA5 | Stuckenia vaginatus (Turcz.) Holub | sheathed pondweed | Potamogetonaceae
|
| STUCK | Stuckenia Boerner | pondweed | Potamogetonaceae
|
| STAB | Stylisma abdita Myint | showy dawnflower | Convolvulaceae
|
| STAN7 | Stylisma angustifolia (Nash) House | Stylisma patens ssp. angustifolia | Convolvulaceae
|
| STAQ3 | Stylisma aquatica (Walt.) Raf. | water dawnflower | Convolvulaceae
|
| STHU2 | Stylisma humistrata (Walt.) Chapman | southern dawnflower | Convolvulaceae
|
| STPAA | Stylisma patens (Desr.) Myint ssp. angustifolia (Nash) Myint | coastalplain dawnflower | Convolvulaceae
|
| STPAP8 | Stylisma patens (Desr.) Myint ssp. patens | coastalplain dawnflower | Convolvulaceae
|
| STPA8 | Stylisma patens (Desr.) Myint | coastalplain dawnflower | Convolvulaceae
|
| STPA16 | Stylisma pattersonii (Fern. & Schub.) G.N. Jones | Stylisma pickeringii var. pattersonii | Convolvulaceae
|
| STPIP2 | Stylisma pickeringii (Torr. ex M.A. Curtis) Gray var. pattersonii (Fern. & Schub.) Myint | Patterson's dawnflower | Convolvulaceae
|
| STPIP3 | Stylisma pickeringii (Torr. ex M.A. Curtis) Gray var. pickeringii | Pickering's dawnflower | Convolvulaceae
|
| STPI3 | Stylisma pickeringii (Torr. ex M.A. Curtis) Gray | Pickering's dawnflower | Convolvulaceae
|
| STTR5 | Stylisma trichosanthes (Michx.) House | Stylisma patens ssp. patens | Convolvulaceae
|
| STVI6 | Stylisma villosa (Nash) House | hairy dawnflower | Convolvulaceae
|
| STYLI | Stylisma Raf. | dawnflower | Convolvulaceae
|
| STAC3 | Stylocline acaulis Kellogg | Hesperevax acaulis var. acaulis | Asteraceae
|
| STAM11 | Stylocline amphiloba (Gray) J.T. Howell | Micropus amphibola | Asteraceae
|
| STCI10 | Stylocline citroleum Morefield | oil neststraw | Asteraceae
|
| STFID | Stylocline filaginea (Gray) Gray var. depressa Jepson | Ancistrocarphus filagineus | Asteraceae
|
| STFI | Stylocline filaginea (Gray) Gray | Ancistrocarphus filagineus | Asteraceae
|
| STGN | Stylocline gnaphalioides Nutt. | mountain neststraw | Asteraceae
|
| STIN4 | Stylocline intertexta Morefield | Morefield's neststraw | Asteraceae
|
| STMA10 | Stylocline masonii Morefield | Mason's neststraw | Asteraceae
|
| STMI2 | Stylocline micropoides Gray | woollyhead neststraw | Asteraceae
|
| STPS | Stylocline psilocarphoides M.E. Peck | baretwig neststraw | Asteraceae
|
| STSO2 | Stylocline sonorensis Wiggins | Sonoran neststraw | Asteraceae
|
| STYLO | Stylocline Nutt. | neststraw | Asteraceae
|
| STCA6 | Stylodon carneus (Medik.) Moldenke | Carolina false vervain | Verbenaceae
|
| STCA21 | Stylodon carolinensis (Walt.) Small | Stylodon carneus | Verbenaceae
|
| STYLO2 | Stylodon Raf. | stylodon | Verbenaceae
|
| STLA4 | Stylogyne lateriflora (Sw.) Mez | quiebrahacha | Myrsinaceae
|
| STYLO6 | Stylogyne A. DC. | stylogyne | Myrsinaceae
|
| STHE3 | Stylomecon heterophylla (Benth.) G. Taylor | windpoppy | Papaveraceae
|
| STYLO5 | Stylomecon G. Taylor | windpoppy | Papaveraceae
|
| STEL4 | Stylopappus elatus Nutt. | Agoseris elata | Asteraceae
|
| STDI3 | Stylophorum diphyllum (Michx.) Nutt. | celandine poppy | Papaveraceae
|
| STYLO3 | Stylophorum Nutt. | stylophorum | Papaveraceae
|
| STAL7 | Stylophyllum albidum Rose | Dudleya virens ssp. virens | Crassulaceae
|
| STED2 | Stylophyllum edule (Nutt.) Britt. & Rose | Dudleya edulis | Crassulaceae
|
| STHA3 | Stylophyllum hassei Rose | Dudleya virens ssp. hassei | Crassulaceae
|
| STIN8 | Stylophyllum insulare Rose | Dudleya virens ssp. insularis | Crassulaceae
|
| STNU3 | Stylophyllum nudicaule Abrams | Dudleya densiflora | Crassulaceae
|
| STOR2 | Stylophyllum orcuttii Rose | Dudleya attenuata ssp. orcuttii | Crassulaceae
|