| Symbol | Scientific name | Common name/Accepted name (for synonyms) | Family |
| SCCH4 | Scoliciosporum chlorococcum (Stenh.) Vezda | | Lecanoraceae
|
| SCSA7 | Scoliciosporum sarothamni (Vainio) Vezda | | Lecanoraceae
|
| SCUMC | Scoliciosporum umbrinum (Ach.) Arnold var. compacta (Korber) Vezda | | Lecanoraceae
|
| SCUM2 | Scoliciosporum umbrinum (Ach.) Arnold | | Lecanoraceae
|
| SCOLI2 | Scoliciosporum A. Massal. | scoliciosporum | Lecanoraceae
|
| SCBI | Scoliopus bigelovii Torr. | California fetid adderstongue | Liliaceae
|
| SCHA2 | Scoliopus hallii S. Wats. | Oregon fetid adderstongue | Liliaceae
|
| SCOLI | Scoliopus Torr. | fetid adderstongue | Liliaceae
|
| SCFE | Scolochloa festucacea (Willd.) Link | common rivergrass | Poaceae
|
| SCOLO | Scolochloa Link | rivergrass | Poaceae
|
| SCDE3 | Scolosanthus densiflorus auct. non Urban | Scolosanthus portoricensis | Rubiaceae
|
| SCGR5 | Scolosanthus grandifolius Krug & Urban | espuela de galan | Rubiaceae
|
| SCMU5 | Scolosanthus multiflorus auct. non (Sw.) Krug & Urban | Scolosanthus grandifolius | Rubiaceae
|
| SCPO9 | Scolosanthus portoricensis Borhidi | maricao | Rubiaceae
|
| SCVE4 | Scolosanthus versicolor Vahl | Puerto Rico devilbrush | Rubiaceae
|
| SCOLO2 | Scolosanthus Vahl | scolosanthus | Rubiaceae
|
| SCGR7 | Scolymus grandiflorus Desf. | Scolymus hispanicus | Asteraceae
|
| SCHI | Scolymus hispanicus L. | common goldenthistle | Asteraceae
|
| SCMA5 | Scolymus maculatus L. | spotted goldenthistle | Asteraceae
|
| SCOLY | Scolymus L. | goldenthistle | Asteraceae
|
| SCDU3 | Scoparia dulcis L. | licorice weed | Scrophulariaceae
|
| SCFL9 | Scoparia flava Cham. & Schlecht. | yellow licorice weed | Scrophulariaceae
|
| SCMOG | Scoparia montevidensis (Spreng.) R.E. Fries var. glandulifera (Fritsch) R.E. Fries | broomwort | Scrophulariaceae
|
| SCMO7 | Scoparia montevidensis (Spreng.) R.E. Fries | broomwort | Scrophulariaceae
|
| SCOPA | Scoparia L. | licorice weed | Scrophulariaceae
|
| SCCA18 | Scopelophila cataractae (Mitt.) Broth. | cataract scopelophila moss | Pottiaceae
|
| SCLA10 | Scopelophila latifolia (Kindb. in Mac.) Ren. & Card. | Crumia latifolia | Pottiaceae
|
| SCLI13 | Scopelophila ligulata (Spruce) Spruce | ligulate scopelophila moss | Pottiaceae
|
| SCOPE | Scopelophila (Mitt.) Lindb. | scopelophila moss | Pottiaceae
|
| SCRI2 | Scopulophila rixfordii (Brandeg.) Munz & Johnston | Rixford's rockwort | Caryophyllaceae
|
| SCOPU | Scopulophila M.E. Jones | rockwort | Caryophyllaceae
|
| SCCO18 | Scorpidium cossonii (Schimp.) Heden�s | Limprichtia cossonii | Amblystegiaceae
|
| SCLA11 | Scorpidium latifolium (Lindb. & Arnell) Paul | Drepanocladus brevifolius | Amblystegiaceae
|
| SCRE7 | Scorpidium revolvens (Sw.) Heden�s | Limprichtia revolvens | Amblystegiaceae
|
| SCSC70 | Scorpidium scorpioides (Hedw.) Limpr. | scorpidium moss | Amblystegiaceae
|
| SCTR8 | Scorpidium trifarium (Web. & Mohr) Paul | Calliergon trifarium | Amblystegiaceae
|
| SCTU70 | Scorpidium turgescens (T. Jens.) Loeske | Pseudocalliergon turgescens | Amblystegiaceae
|
| SCVE7 | Scorpidium vernicosum (Mitt.) Tuom. | Hamatocaulis vernicosus | Amblystegiaceae
|
| SCORP2 | Scorpidium (Schimp.) Limpr. | scorpidium moss | Amblystegiaceae
|
| SCMU3 | Scorpiurus muricatus L. | prickly scorpion's-tail | Fabaceae
|
| SCSU5 | Scorpiurus subvillosus L. | Scorpiurus muricatus | Fabaceae
|
| SCSU3 | Scorpiurus sulcatus L. | Scorpiurus muricatus | Fabaceae
|
| SCORP | Scorpiurus L. | scorpion's-tail | Fabaceae
|
| SCLAB | Scorzonella laciniata (Hook.) Schultz-Bip. var. bolanderi (Gray) Jepson | Microseris laciniata ssp. leptosepala | Asteraceae
|
| SCLAP | Scorzonella laciniata (Hook.) Schultz-Bip. var. pratensis (Greene) Jepson | Microseris laciniata ssp. laciniata | Asteraceae
|
| SCLA7 | Scorzonella laciniata (Hook.) Schultz-Bip. | Microseris laciniata ssp. laciniata | Asteraceae
|
| SCLE2 | Scorzonella leachiana M.E. Peck | Microseris laciniata ssp. leptosepala | Asteraceae
|
| SCLE4 | Scorzonella leptosepala Nutt. | Microseris laciniata ssp. leptosepala | Asteraceae
|
| SCNUM | Scorzonella nutans Hook. var. major (Gray) M.E. Peck | Microseris nutans | Asteraceae
|
| SCNU4 | Scorzonella nutans Hook. | Microseris nutans | Asteraceae
|
| SCPR2 | Scorzonella procera Greene | Microseris laciniata ssp. laciniata | Asteraceae
|
| SCTR6 | Scorzonella troximoides (Gray) Jepson | Nothocalais troximoides | Asteraceae
|
| SCHI2 | Scorzonera hispanica L. | black salsify | Asteraceae
|
| SCLA6 | Scorzonera laciniata L. | cutleaf vipergrass | Asteraceae
|
| SCORZ | Scorzonera L. | scorzonera | Asteraceae
|
| SCAQ2 | Scouleria aquatica Hook. in Drumm. | blackmat splashzone moss | Scouleriaceae
|
| SCMA10 | Scouleria marginata Britt. | marginate splashzone moss | Scouleriaceae
|
| SCOUL | Scouleria Hook. in Drumm. | splashzone moss | Scouleriaceae
|
| SCBO | Scribneria bolanderi (Thurb.) Hack. | Scribner's grass | Poaceae
|
| SCRIB | Scribneria Hack. | Scribner's grass | Poaceae
|
| SCAQ | Scrophularia aquatica L. | Scrophularia umbrosa | Scrophulariaceae
|
| SCAT3 | Scrophularia atrata Pennell | darkflowered figwort | Scrophulariaceae
|
| SCAU7 | Scrophularia auriculata L. | shoreline figwort | Scrophulariaceae
|
| SCCAC | Scrophularia californica Cham. & Schlecht. ssp. californica | California figwort | Scrophulariaceae
|
| SCCAF2 | Scrophularia californica Cham. & Schlecht. ssp. floribunda (Greene) R.J. Shaw | California figwort | Scrophulariaceae
|
| SCCAD | Scrophularia californica Cham. & Schlecht. var. desertorum Munz | Scrophularia desertorum | Scrophulariaceae
|
| SCCAF | Scrophularia californica Cham. & Schlecht. var. floribunda Greene | Scrophularia californica ssp. floribunda | Scrophulariaceae
|
| SCCAL | Scrophularia californica Cham. & Schlecht. var. laciniata Jepson | Scrophularia californica ssp. floribunda | Scrophulariaceae
|
| SCCAO | Scrophularia californica Cham. & Schlecht. var. oregana (Pennell) Boivin | Scrophularia oregana | Scrophulariaceae
|
| SCCA2 | Scrophularia californica Cham. & Schlecht. | California figwort | Scrophulariaceae
|
| SCCAC2 | Scrophularia canina L. ssp. canina | dog figwort | Scrophulariaceae
|
| SCCAH | Scrophularia canina L. ssp. hoppii (Koch) Fourn. | Hopp's figwort | Scrophulariaceae
|
| SCCA20 | Scrophularia canina L. | dog figwort | Scrophulariaceae
|
| SCCO5 | Scrophularia coccinea Gray | Scrophularia macrantha | Scrophulariaceae
|
| SCDA | Scrophularia davidsonii Pennell | Scrophularia parviflora | Scrophulariaceae
|
| SCDE | Scrophularia desertorum (Munz) R.J. Shaw | desert figwort | Scrophulariaceae
|
| SCFL8 | Scrophularia floribunda (Greene) Heller | Scrophularia californica ssp. floribunda | Scrophulariaceae
|
| SCGL9 | Scrophularia glabrata A. Davids. | Scrophularia parviflora | Scrophulariaceae
|
| SCHO5 | Scrophularia hoppii Koch | Scrophularia canina ssp. hoppii | Scrophulariaceae
|
| SCLA5 | Scrophularia laevis Woot. & Standl. | Organ Mountain figwort | Scrophulariaceae
|
| SCLA | Scrophularia lanceolata Pursh | lanceleaf figwort | Scrophulariaceae
|
| SCMA7 | Scrophularia macrantha Greene ex Stiefelhagen | New Mexico figwort | Scrophulariaceae
|
| SCMA2 | Scrophularia marilandica L. | carpenter's square | Scrophulariaceae
|
| SCMI8 | Scrophularia minutiflora Pennell | littleflower figwort | Scrophulariaceae
|
| SCMO4 | Scrophularia montana Woot. | Montana figwort | Scrophulariaceae
|
| SCMU9 | Scrophularia multiflora Pennell | Scrophularia californica ssp. floribunda | Scrophulariaceae
|
| SCNE3 | Scrophularia neomexicana R.J. Shaw | Scrophularia macrantha | Scrophulariaceae
|
| SCNOC | Scrophularia nodosa L. var. californica (Cham. & Schlecht.) M.E. Jones | Scrophularia californica ssp. californica | Scrophulariaceae
|
| SCNO2 | Scrophularia nodosa L. | woodland figwort | Scrophulariaceae
|
| SCOR | Scrophularia oregana Pennell | Oregon figwort | Scrophulariaceae
|
| SCPA6 | Scrophularia parviflora Woot. & Standl. | pineland figwort | Scrophulariaceae
|
| SCPE8 | Scrophularia pectinata Raf. | Scrophularia lanceolata | Scrophulariaceae
|
| SCPE11 | Scrophularia peregrina L. | Mediterranean figwort | Scrophulariaceae
|
| SCUM | Scrophularia umbrosa Dumort. | water figwort | Scrophulariaceae
|
| SCVI | Scrophularia villosa Pennell | Santa Catalina figwort | Scrophulariaceae
|
| SCROP | Scrophularia L. | figwort | Scrophulariaceae
|
| SCAL2 | Scutellaria alabamensis Alexander | Alabama skullcap | Lamiaceae
|
| SCALA | Scutellaria altamaha Small ssp. australis Epling | Scutellaria incana var. australis | Lamiaceae
|
| SCAL3 | Scutellaria altamaha Small | pineland skullcap | Lamiaceae
|
| SCAL4 | Scutellaria altissima L. | tall skullcap | Lamiaceae
|
| SCAM4 | Scutellaria ambigua Nutt. | Scutellaria parvula var. missouriensis | Lamiaceae
|