| Symbol | Scientific name | Common name/Accepted name (for synonyms) | Family |
| STTR6 | Stylophyllum traskiae Rose | Dudleya traskiae | Crassulaceae
|
| STVI12 | Stylophyllum virens Rose | Dudleya virens ssp. virens | Crassulaceae
|
| STVI9 | Stylophyllum viscidum (S. Wats.) Britt. & Rose | Dudleya viscida | Crassulaceae
|
| STBIH | Stylosanthes biflora (L.) B.S.P. var. hispidissima (Michx.) Pollard & Ball | Stylosanthes biflora | Fabaceae
|
| STBI2 | Stylosanthes biflora (L.) B.S.P. | sidebeak pencilflower | Fabaceae
|
| STCA7 | Stylosanthes calcicola Small | Everglade Key pencilflower | Fabaceae
|
| STER2 | Stylosanthes erecta Beauv. | Nigerian stylo | Fabaceae
|
| STFL3 | Stylosanthes floridana Blake | Stylosanthes biflora | Fabaceae
|
| STFR80 | Stylosanthes fruticosa (Retz.) Alston | shrubby pencilflower | Fabaceae
|
| STGR12 | Stylosanthes gracilis Kunth | Stylosanthes erecta | Fabaceae
|
| STGU80 | Stylosanthes guianensis (Aubl.) Sw. | Stylosanthes erecta | Fabaceae
|
| STGU2 | Stylosanthes guineensis Schumacher | Stylosanthes erecta | Fabaceae
|
| STHA | Stylosanthes hamata (L.) Taubert | cheesytoes | Fabaceae
|
| STHU4 | Stylosanthes humilis Kunth | Townsville stylo | Fabaceae
|
| STMU3 | Stylosanthes mucronata Willd. | Stylosanthes fruticosa | Fabaceae
|
| STRIS | Stylosanthes riparia Kearney var. setifera Fern. | Stylosanthes biflora | Fabaceae
|
| STRI3 | Stylosanthes riparia Kearney | Stylosanthes biflora | Fabaceae
|
| STSC8 | Stylosanthes scabra Vog. | pencilflower | Fabaceae
|
| STSU6 | Stylosanthes subsericea Blake | pencilflower | Fabaceae
|
| STVI5 | Stylosanthes viscosa (L.) Sw. | poorman's friend | Fabaceae
|
| STYLO4 | Stylosanthes Sw. | pencilflower | Fabaceae
|
| STVE2 | Stylypus vernus Raf. | Geum vernum | Rosaceae
|
| STDO | Styphelia douglasii (Gray) F. Muell. ex Skottsberg | Styphelia tameiameiae | Epacridaceae
|
| STTAB | Styphelia tameiameiae (Cham. & Schlecht.) F. Muell. var. brownii (Gray) St. John | Styphelia tameiameiae | Epacridaceae
|
| STTAH | Styphelia tameiameiae (Cham. & Schlecht.) F. Muell. var. hexandra Fosberg & Hosaka | Styphelia tameiameiae | Epacridaceae
|
| STTA | Styphelia tameiameiae (Cham. & Schlecht.) F. Muell. | pukiawe | Epacridaceae
|
| STYPH | Styphelia Sm. | styphelia | Epacridaceae
|
| STAMP2 | Styrax americanus Lam. var. pulverulentus (Michx.) Perkins ex Rehd. | Styrax americanus | Styracaceae
|
| STAM4 | Styrax americanus Lam. | American snowbell | Styracaceae
|
| STBE3 | Styrax benzoides Craib | Siam benzoin | Styracaceae
|
| STBE4 | Styrax benzoin Dryander | styrax | Styracaceae
|
| STCAF2 | Styrax californicus Torr. var. fulvescens Eastw. | Styrax rediviva | Styracaceae
|
| STCA20 | Styrax californicus Torr. | Styrax rediviva | Styracaceae
|
| STGR4 | Styrax grandifolius Ait. | bigleaf snowbell | Styracaceae
|
| STJA5 | Styrax japonicus Sieb. & Zucc. | Japanese snowbell | Styracaceae
|
| STOFF2 | Styrax officinalis L. ssp. fulvescens (Eastw.) Beauchamp | Styrax rediviva | Styracaceae
|
| STOFC2 | Styrax officinalis L. var. californicus (Torr.) Rehd. | Styrax rediviva | Styracaceae
|
| STOFF | Styrax officinalis L. var. fulvescens (Eastw.) Munz & Johnston | Styrax rediviva | Styracaceae
|
| STOFR | Styrax officinalis L. var. redivivus (Torr.) Howard | Styrax rediviva | Styracaceae
|
| STPLP2 | Styrax platanifolius Engelm. ex Torr. ssp. platanifolius | sycamoreleaf snowbell | Styracaceae
|
| STPLS2 | Styrax platanifolius Engelm. ex Torr. ssp. stellatus (Cory) P.W. Fritsch | sycamoreleaf snowbell | Styracaceae
|
| STPLT | Styrax platanifolius Engelm. ex Torr. ssp. texanus (Cory) P.W. Fritsch | Texas snowbell | Styracaceae
|
| STPLY | Styrax platanifolius Engelm. ex Torr. ssp. youngiae (Cory) P.W. Fritsch | Young's snowbell | Styracaceae
|
| STPLS | Styrax platanifolius Engelm. ex Torr. var. stellatus Cory | Styrax platanifolius ssp. stellatus | Styracaceae
|
| STPL3 | Styrax platanifolius Engelm. ex Torr. | sycamoreleaf snowbell | Styracaceae
|
| STPO3 | Styrax portoricensis Krug & Urban | palo de jazmin | Styracaceae
|
| STPU6 | Styrax pulverulentus Michx. | Styrax americanus | Styracaceae
|
| STRE4 | Styrax rediviva (Torr.) Wheeler | drug snowbell | Styracaceae
|
| STTE5 | Styrax texanus Cory | Styrax platanifolius ssp. texanus | Styracaceae
|
| STTO7 | Styrax tonkinensis (Pierre) Craib ex Hartwich | Siam benzoin | Styracaceae
|
| STYO | Styrax youngiae Cory | Styrax platanifolius ssp. youngiae | Styracaceae
|
| STYRA | Styrax L. | snowbell | Styracaceae
|
| SUAM | Suaeda americana (Pers.) Fern. | Suaeda calceoliformis | Chenopodiaceae
|
| SUCA2 | Suaeda calceoliformis (Hook.) Moq. | Pursh seepweed | Chenopodiaceae
|
| SUCAP | Suaeda californica S. Wats. var. pubescens Jepson | Suaeda taxifolia | Chenopodiaceae
|
| SUCAT | Suaeda californica S. Wats. var. taxifolia (Standl.) Munz | Suaeda taxifolia | Chenopodiaceae
|
| SUCA | Suaeda californica S. Wats. | California seablite | Chenopodiaceae
|
| SUCO | Suaeda conferta (Small) I.M. Johnston | beach seepweed | Chenopodiaceae
|
| SUDEE | Suaeda depressa (Pursh) S. Wats. var. erecta S. Wats. | Suaeda calceoliformis | Chenopodiaceae
|
| SUDE | Suaeda depressa auct. non (Pursh) S. Wats. | Suaeda calceoliformis | Chenopodiaceae
|
| SUDU | Suaeda duripes I.M. Johnston | Suaeda suffrutescens var. detonsa | Chenopodiaceae
|
| SUES | Suaeda esteroa Ferren & Whitmore | seablite | Chenopodiaceae
|
| SUFR2 | Suaeda fruticosa auct. non Forsk. | Suaeda moquinii | Chenopodiaceae
|
| SUIN | Suaeda intermedia S. Wats. | Suaeda moquinii | Chenopodiaceae
|
| SULI | Suaeda linearis (Ell.) Moq. | annual seepweed | Chenopodiaceae
|
| SUMAM | Suaeda maritima (L.) Dumort. ssp. maritima | herbaceous seepweed | Chenopodiaceae
|
| SUMAR | Suaeda maritima (L.) Dumort. ssp. richii (Fern.) Bassett & C.W. Crompton | Rich's seepweed | Chenopodiaceae
|
| SUMAA | Suaeda maritima (L.) Dumort. var. americana (Pers.) Boivin | Suaeda calceoliformis | Chenopodiaceae
|
| SUMA | Suaeda maritima (L.) Dumort. | herbaceous seepweed | Chenopodiaceae
|
| SUME | Suaeda mexicana (Standl.) Standl. | Mexican seepweed | Chenopodiaceae
|
| SUMI | Suaeda minutiflora S. Wats. | Suaeda calceoliformis | Chenopodiaceae
|
| SUMO | Suaeda moquinii (Torr.) Greene | Mojave seablite | Chenopodiaceae
|
| SUNI | Suaeda nigra J.F. Macbr. | Suaeda moquinii | Chenopodiaceae
|
| SUNIG | Suaeda nigrescens I.M. Johnston var. glabra I.M. Johnston | Suaeda suffrutescens var. detonsa | Chenopodiaceae
|
| SUNI2 | Suaeda nigrescens I.M. Johnston | Suaeda suffrutescens var. detonsa | Chenopodiaceae
|
| SUOC | Suaeda occidentalis (S. Wats.) S. Wats. | Suaeda calceoliformis | Chenopodiaceae
|
| SUPR2 | Suaeda prostrata Pallas | Suaeda maritima ssp. maritima | Chenopodiaceae
|
| SURA2 | Suaeda ramosissima (Standl.) I.M. Johnston | Suaeda moquinii | Chenopodiaceae
|
| SURI | Suaeda richii Fern. | Suaeda maritima ssp. richii | Chenopodiaceae
|
| SURO | Suaeda rolandii Bassett & C.W. Crompton | Roland's seablite | Chenopodiaceae
|
| SUSUD | Suaeda suffrutescens S. Wats. var. detonsa I.M. Johnston | desert seepweed | Chenopodiaceae
|
| SUSUS | Suaeda suffrutescens S. Wats. var. suffrutescens | desert seepweed | Chenopodiaceae
|
| SUSU | Suaeda suffrutescens S. Wats. | desert seepweed | Chenopodiaceae
|
| SUTA | Suaeda tampicensis (Standl.) Standl. | coastal seepweed | Chenopodiaceae
|
| SUTAB | Suaeda taxifolia (Standl.) Standl. ssp. brevifolia (Standl.) Abrams | Suaeda taxifolia | Chenopodiaceae
|
| SUTA2 | Suaeda taxifolia (Standl.) Standl. | woolly seablite | Chenopodiaceae
|
| SUTOR | Suaeda torreyana S. Wats. var. ramosissima (Standl.) Munz | Suaeda moquinii | Chenopodiaceae
|
| SUTO | Suaeda torreyana S. Wats. | Suaeda moquinii | Chenopodiaceae
|
| SUVE2 | Suaeda vera Forssk. ex J.F. Gmel. | alkali seepweed | Chenopodiaceae
|
| SUAED | Suaeda Forsk. ex J.F. Gmel. | seepweed | Chenopodiaceae
|
| SUAQA | Subularia aquatica L. ssp. americana Mulligan & Calder | Subularia aquatica var. americana | Brassicaceae
|
| SUAQA2 | Subularia aquatica L. var. americana (Mulligan & Calder) Boivin | American waterawlwort | Brassicaceae
|
| SUAQ | Subularia aquatica L. | waterawlwort | Brassicaceae
|
| SUBUL | Subularia L. | awlwort | Brassicaceae
|
| SUAU | Succisa australis (Wulfen) Reichenb. | Succisella inflexa | Dipsacaceae
|
| SUPR | Succisa pratensis Moench | devilsbit | Dipsacaceae
|
| SUCCI | Succisa Haller | succisa | Dipsacaceae
|
| SUIN2 | Succisella inflexa (Kluk) G. Beck | southern succisella | Dipsacaceae
|
| SUCCI2 | Succisella G. Beck | succisella | Dipsacaceae
|
| SUSU2 | Suckleya suckleyana (Torr.) Rydb. | poison suckleya | Chenopodiaceae
|
| SUCKL | Suckleya Gray | suckleya | Chenopodiaceae
|