| Symbol | Scientific name | Common name/Accepted name (for synonyms) | Family |
| STSY4 | Sticta sylvatica (Hudson) Ach. | spotted felt lichen | Lobariaceae
|
| STVE4 | Sticta verrucosa (Hudson) Fink | Lobaria scrobiculata | Lobariaceae
|
| STWR4 | Sticta wrightii Tuck. | Wright's spotted felt lichen | Lobariaceae
|
| STICT2 | Sticta (Schreber) Ach. | spotted felt lichen | Lobariaceae
|
| STCA18 | Stictocardia campanulata auct. non (L.) Merr. | Stictocardia tiliifolia | Convolvulaceae
|
| STTI | Stictocardia tiliifolia (Desr.) Hallier f. | spottedheart | Convolvulaceae
|
| STICT | Stictocardia Hallier f. | stictocardia | Convolvulaceae
|
| STBA7 | Stigmaphyllon bannisterioides (L.) C. Anderson | eggleaf Amazonvine | Malpighiaceae
|
| STCO8 | Stigmaphyllon cordifolium Niedenzu | Stigmaphyllon diversifolium | Malpighiaceae
|
| STDI7 | Stigmaphyllon diversifolium (Kunth) A. Juss. | heartleaf Amazonvine | Malpighiaceae
|
| STEM3 | Stigmaphyllon emarginatum (Cav.) A. Juss. | monarch Amazonvine | Malpighiaceae
|
| STFL5 | Stigmaphyllon floribundum (DC.) C. Anderson | woolly Amazonvine | Malpighiaceae
|
| STLE7 | Stigmaphyllon ledifolium (Kunth) Small | Stigmaphyllon diversifolium | Malpighiaceae
|
| STLI7 | Stigmaphyllon lingulatum (Poir.) Small | Stigmaphyllon emarginatum | Malpighiaceae
|
| STOV2 | Stigmaphyllon ovatum (Cav.) Niedenzu | Stigmaphyllon bannisterioides | Malpighiaceae
|
| STPE2 | Stigmaphyllon periplocifolium (Desf. ex DC.) A. Juss. | Stigmaphyllon emarginatum | Malpighiaceae
|
| STPU3 | Stigmaphyllon puberum (L.C. Rich.) A. Juss. | South American Amazonvine | Malpighiaceae
|
| STRU5 | Stigmaphyllon rubrinervum Alain | Stigmaphyllon emarginatum | Malpighiaceae
|
| STTO4 | Stigmaphyllon tomentosum (Desf.) Niedenzu | Stigmaphyllon floribundum | Malpighiaceae
|
| STIGM | Stigmaphyllon A. Juss. | Amazonvine | Malpighiaceae
|
| STAT4 | Stigmidium atryneae (Arnold) Hafellner | | Mycosphaerellaceae
|
| STCO21 | Stigmidium congestum (Korber) Triebel | | Mycosphaerellaceae
|
| STEP2 | Stigmidium ephebes (Henssen) D. Hawksw. | | Mycosphaerellaceae
|
| STFR2 | Stigmidium frigidum (Sacc.) Alstrup & D. Hawksw. | | Mycosphaerellaceae
|
| STFU3 | Stigmidium fuscatae (Arnold) R. Sant. | | Mycosphaerellaceae
|
| STMA9 | Stigmidium marinum (Deakin) Swinscow | | Mycosphaerellaceae
|
| STPA19 | Stigmidium parva (Henssen) | | Mycosphaerellaceae
|
| STPS2 | Stigmidium psorae (Anzi) Hafellner | | Mycosphaerellaceae
|
| STTA2 | Stigmidium tabacinae (Arnold) Triebel | | Mycosphaerellaceae
|
| STIGM2 | Stigmidium Trevisan | stigmidium | Mycosphaerellaceae
|
| STAN6 | Stillingia angustifolia (Torr.) Engelm. ex S. Wats. | Stillingia sylvatica ssp. sylvatica | Euphorbiaceae
|
| STAQ2 | Stillingia aquatica Chapman | water toothleaf | Euphorbiaceae
|
| STLI3 | Stillingia linearifolia S. Wats. | queen's-root | Euphorbiaceae
|
| STPA5 | Stillingia paucidentata S. Wats. | Mojave toothleaf | Euphorbiaceae
|
| STSA5 | Stillingia salicifolia (Torr.) Raf. | Stillingia sylvatica ssp. sylvatica | Euphorbiaceae
|
| STSP11 | Stillingia spathulata (Muell.-Arg.) Small | Stillingia sylvatica ssp. sylvatica | Euphorbiaceae
|
| STSP | Stillingia spinulosa Torr. | annual toothleaf | Euphorbiaceae
|
| STSYS2 | Stillingia sylvatica Garden ex L. ssp. sylvatica | queen's-delight | Euphorbiaceae
|
| STSYT | Stillingia sylvatica Garden ex L. ssp. tenuis (Small) D.J. Rogers | queen's-delight | Euphorbiaceae
|
| STSYL | Stillingia sylvatica Garden ex L. var. linearifolia (Torr.) Muell.-Arg. | Stillingia texana | Euphorbiaceae
|
| STSYS | Stillingia sylvatica Garden ex L. var. salicifolia Torr. | Stillingia sylvatica ssp. sylvatica | Euphorbiaceae
|
| STSY | Stillingia sylvatica Garden ex L. | queen's-delight | Euphorbiaceae
|
| STTE11 | Stillingia tenuis Small | Stillingia sylvatica ssp. tenuis | Euphorbiaceae
|
| STTE3 | Stillingia texana I.M. Johnston | Texas toothleaf | Euphorbiaceae
|
| STTR2 | Stillingia treculiana (Muell.-Arg.) I.M. Johnston | Trecul's toothleaf | Euphorbiaceae
|
| STILL | Stillingia Garden ex L. | toothleaf | Euphorbiaceae
|
| STAR2 | Stipa arida M.E. Jones | Achnatherum aridum | Poaceae
|
| STAV | Stipa avenacea L. | Piptochaetium avenaceum | Poaceae
|
| STAV2 | Stipa avenacioides Nash | Piptochaetium avenacioides | Poaceae
|
| STBL4 | Stipa bloomeri Boland. | Achnatherum bloomeri | Poaceae
|
| STBR3 | Stipa brachychaeta Godr. | Achnatherum brachychaetum | Poaceae
|
| STBR9 | Stipa breviflora Griseb. | needlegrass | Poaceae
|
| STCA22 | Stipa caduca (Beal) Scribn. | � Achnella caduca | Poaceae
|
| STCA2 | Stipa californica Merr. & Burtt-Davy ex Hall | Achnatherum occidentale ssp. californicum | Poaceae
|
| STCA19 | Stipa canadensis Poir. | Piptatherum canadense | Poaceae
|
| STCA25 | Stipa capensis Thunb. | Achnatherum capense | Poaceae
|
| STCAG | Stipa caucasica Schmalh. ssp. glareosa (P.Smirn.) Tzvel. | needlegrass | Poaceae
|
| STCA35 | Stipa caucasica Schmalh. | needlegrass | Poaceae
|
| STCE | Stipa cernua Stebbins & R.M. Love | Nassella cernua | Poaceae
|
| STCL5 | Stipa clandestina Hack. | Achnatherum clandestinum | Poaceae
|
| STCON2 | Stipa columbiana Macoun var. nelsonii (Scribn.) St. John | Achnatherum nelsonii ssp. nelsonii | Poaceae
|
| STCO3 | Stipa columbiana auct. non Macoun | Achnatherum nelsonii ssp. dorei | Poaceae
|
| STCOI2 | Stipa comata Trin. & Rupr. ssp. intonsa Piper | Hesperostipa comata ssp. comata | Poaceae
|
| STCOF | Stipa comata Trin. & Rupr. var. falcata Boivin p.p. | Hesperostipa comata ssp. intermedia | Poaceae
|
| STCOI | Stipa comata Trin. & Rupr. var. intermedia Scribn. & Tweedy | Hesperostipa comata ssp. intermedia | Poaceae
|
| STCOS | Stipa comata Trin. & Rupr. var. suksdorfii St. John | Hesperostipa comata ssp. intermedia | Poaceae
|
| STCO4 | Stipa comata Trin. & Rupr. | Hesperostipa comata ssp. comata | Poaceae
|
| STCO11 | Stipa contracta (B.L. Johnson) W.A. Weber | Achnatherum contractum | Poaceae
|
| STCOD | Stipa coronata Thurb. var. depauperata (M.E. Jones) A.S. Hitchc. | Achnatherum parishii var. depauperatum | Poaceae
|
| STCOP2 | Stipa coronata Thurb. var. parishii (Vasey) A.S. Hitchc. | Achnatherum parishii var. parishii | Poaceae
|
| STCO5 | Stipa coronata Thurb. | Achnatherum coronatum | Poaceae
|
| STCU4 | Stipa curtiseta (A.S. Hitchc.) Barkworth | Hesperostipa curtiseta | Poaceae
|
| STCU2 | Stipa curvifolia Swallen | Achnatherum curvifolium | Poaceae
|
| STDI | Stipa diegoensis Swallen | Achnatherum diegoense | Poaceae
|
| STEL7 | Stipa elegantissima Labill. | Australian needlegrass | Poaceae
|
| STEL2 | Stipa elmeri Piper & Brodie ex Scribn. | Achnatherum occidentale ssp. pubescens | Poaceae
|
| STEM2 | Stipa eminens Cav. | Achnatherum eminens | Poaceae
|
| STFI4 | Stipa fimbriata Kunth | Piptochaetium fimbriatum | Poaceae
|
| STGL7 | Stipa glareosa P. Smirn. | Stipa caucasica ssp. glareosa | Poaceae
|
| STGR13 | Stipa grandis P. Smirn. | needlegrass | Poaceae
|
| STHE5 | Stipa hendersonii (Vasey) Muhl. | Achnatherum hendersonii | Poaceae
|
| STHY6 | Stipa hymenoides Roemer & J.A. Schultes | Achnatherum hymenoides | Poaceae
|
| STIC | Stipa ichu (Ruiz & Pav�n) Kunth | Peruvian feathergrass | Poaceae
|
| STKI | Stipa kingii Boland. | Ptilagrostis kingii | Poaceae
|
| STKL | Stipa klemenzii Roshev. | needlegrass | Poaceae
|
| STKR | Stipa krylovii Roshev. | needlegrass | Poaceae
|
| STLA2 | Stipa latiglumis Swallen | Achnatherum latiglume | Poaceae
|
| STLEJ | Stipa lemmonii (Vasey) Scribn. var. jonesii Scribn. | Achnatherum lemmonii var. lemmonii | Poaceae
|
| STLEP | Stipa lemmonii (Vasey) Scribn. var. pubescens Crampton | Achnatherum lemmonii var. pubescens | Poaceae
|
| STLE2 | Stipa lemmonii (Vasey) Scribn. | Achnatherum lemmonii var. lemmonii | Poaceae
|
| STLEA | Stipa lepida A.S. Hitchc. var. andersonii (Vasey) A.S. Hitchc. | Nassella lepida | Poaceae
|
| STLE3 | Stipa lepida A.S. Hitchc. | Nassella lepida | Poaceae
|
| STLE4 | Stipa lettermanii Vasey | Achnatherum lettermanii | Poaceae
|
| STLE5 | Stipa leucotricha Trin. & Rupr. | Nassella leucotricha | Poaceae
|
| STLI4 | Stipa littoralis Phil. | Achnatherum caudatum | Poaceae
|
| STLO3 | Stipa lobata Swallen | Achnatherum lobatum | Poaceae
|
| STMI6 | Stipa minor (Vasey) Scribn. | Achnatherum nelsonii ssp. dorei | Poaceae
|
| STNE | Stipa neesiana Trin. & Rupr. | Nassella neesiana | Poaceae
|
| STNED | Stipa nelsonii Scribn. ssp. dorei Barkworth & Maze | Achnatherum nelsonii ssp. dorei | Poaceae
|
| STNED2 | Stipa nelsonii Scribn. var. dorei (Barkworth & Maze) Dorn | Achnatherum nelsonii ssp. dorei | Poaceae
|
| STNEL3 | Stipa nelsonii Scribn. var. longiaristata Barkworth & Maze | Achnatherum occidentale ssp. californicum | Poaceae
|