| Symbol | Scientific name | Common name/Accepted name (for synonyms) | Family |
| SIASS | Silphium asteriscus L. var. scabrum Nutt. | Silphium asteriscus var. asteriscus | Asteraceae
|
| SIAS2 | Silphium asteriscus L. | starry rosinweed | Asteraceae
|
| SIAT4 | Silphium atropurpureum Retz. ex Willd. | Silphium trifoliatum var. trifoliatum | Asteraceae
|
| SIBR2 | Silphium brachiatum Gattinger | Cumberland rosinweed | Asteraceae
|
| SICH3 | Silphium chickamaugense Canby | Silphium pinnatifidum | Asteraceae
|
| SICOO | Silphium compositum Michx. ssp. ovatifolium (Torr. & Gray) Sweeny & T.R. Fisher | Silphium compositum var. ovatifolium | Asteraceae
|
| SICOR | Silphium compositum Michx. ssp. reniforme (Raf. ex Nutt.) Sweeny & T.R. Fisher | Silphium compositum var. reniforme | Asteraceae
|
| SICOV | Silphium compositum Michx. ssp. venosum (Small) Sweeny & T.R. Fisher | Silphium compositum var. venosum | Asteraceae
|
| SICOC | Silphium compositum Michx. var. compositum | kidneyleaf rosinweed | Asteraceae
|
| SICOO2 | Silphium compositum Michx. var. ovatifolium Torr. & Gray | kidneyleaf rosinweed | Asteraceae
|
| SICOR2 | Silphium compositum Michx. var. reniforme (Raf. ex Nutt.) Torr. & Gray | kidneyleaf rosinweed | Asteraceae
|
| SICOV2 | Silphium compositum Michx. var. venosum (Small) Kartesz & Gandhi | kidneyleaf rosinweed | Asteraceae
|
| SICO5 | Silphium compositum Michx. | kidneyleaf rosinweed | Asteraceae
|
| SICO12 | Silphium confertifolium Small | Silphium trifoliatum var. latifolium | Asteraceae
|
| SICO11 | Silphium connatum L. | Silphium perfoliatum var. connatum | Asteraceae
|
| SIDEA | Silphium dentatum Ell. var. angustatum (Gray) Perry | Silphium asteriscus var. angustatum | Asteraceae
|
| SIDEG | Silphium dentatum Ell. var. gatesii (C. Mohr) Ahles | Silphium radula | Asteraceae
|
| SIDE8 | Silphium dentatum Ell. | Silphium asteriscus var. laevicaule | Asteraceae
|
| SIEL4 | Silphium elliottii Small | Silphium asteriscus var. laevicaule | Asteraceae
|
| SIGA2 | Silphium gatesii C. Mohr | Silphium radula | Asteraceae
|
| SIGL8 | Silphium glabrum Eggert ex Small | Silphium trifoliatum var. latifolium | Asteraceae
|
| SIGR4 | Silphium gracile Gray | slender rosinweed | Asteraceae
|
| SIIN19 | Silphium incisum Greene | Silphium asteriscus var. laevicaule | Asteraceae
|
| SIIND | Silphium integrifolium Michx. var. deamii Perry | Deam's rosinweed | Asteraceae
|
| SIING | Silphium integrifolium Michx. var. gattingeri Perry | Gattinger's rosinweed | Asteraceae
|
| SIINI | Silphium integrifolium Michx. var. integrifolium | wholeleaf rosinweed | Asteraceae
|
| SIINL | Silphium integrifolium Michx. var. laeve Torr. & Gray | wholeleaf rosinweed | Asteraceae
|
| SIINN | Silphium integrifolium Michx. var. neglectum Settle & T.R. Fisher | wholeleaf rosinweed | Asteraceae
|
| SIIN2 | Silphium integrifolium Michx. | wholeleaf rosinweed | Asteraceae
|
| SILAL2 | Silphium laciniatum L. var. laciniatum | compassplant | Asteraceae
|
| SILAR | Silphium laciniatum L. var. robinsonii Perry | Robinson's compassplant | Asteraceae
|
| SILA3 | Silphium laciniatum L. | compassplant | Asteraceae
|
| SILA17 | Silphium laevigatum Ell., non Pursh | Silphium trifoliatum var. trifoliatum | Asteraceae
|
| SILA13 | Silphium laevigatum Pursh | Silphium integrifolium var. integrifolium | Asteraceae
|
| SILA14 | Silphium lapsuum Small | Silphium compositum var. venosum | Asteraceae
|
| SIMO4 | Silphium mohrii Small | Mohr's rosinweed | Asteraceae
|
| SINO2 | Silphium nodum Small | Silphium asteriscus var. laevicaule | Asteraceae
|
| SIOR5 | Silphium orae Small | Silphium compositum var. compositum | Asteraceae
|
| SIOV2 | Silphium ovatifolium (Torr. & Gray) Small | Silphium compositum var. ovatifolium | Asteraceae
|
| SIPEC | Silphium perfoliatum L. ssp. connatum (L.) Cruden | Silphium perfoliatum var. connatum | Asteraceae
|
| SIPEC2 | Silphium perfoliatum L. var. connatum (L.) Cronq. | cup plant | Asteraceae
|
| SIPEP | Silphium perfoliatum L. var. perfoliatum | cup plant | Asteraceae
|
| SIPE2 | Silphium perfoliatum L. | cup plant | Asteraceae
|
| SIPI2 | Silphium pinnatifidum Ell. | tansy rosinweed | Asteraceae
|
| SIRA2 | Silphium radula Nutt. | roughstem rosinweed | Asteraceae
|
| SIRE9 | Silphium reniforme Raf. ex Nutt. | Silphium compositum var. reniforme | Asteraceae
|
| SIRE4 | Silphium reverchonii Bush | Reverchon's rosinweed | Asteraceae
|
| SIRU3 | Silphium rumicifolium Small | Silphium terebinthinaceum var. terebinthinaceum | Asteraceae
|
| SISC4 | Silphium scaberrimum Ell. | roughleaf rosinweed | Asteraceae
|
| SISC5 | Silphium scabrum Moench, non Walt. | Silphium perfoliatum var. connatum | Asteraceae
|
| SISIW | Silphium simpsonii Greene var. wrightii Perry | Silphium gracile | Asteraceae
|
| SISI | Silphium simpsonii Greene | Simpson's rosinweed | Asteraceae
|
| SISP3 | Silphium speciosum Nutt. | Silphium integrifolium var. laeve | Asteraceae
|
| SITEL2 | Silphium terebinthinaceum Jacq. var. luciae-brauniae Steyermark | Lucy Braun's rosinweed | Asteraceae
|
| SITEP | Silphium terebinthinaceum Jacq. var. pinnatifidum (Ell.) Gray | Silphium pinnatifidum | Asteraceae
|
| SITET | Silphium terebinthinaceum Jacq. var. terebinthinaceum | prairie rosinweed | Asteraceae
|
| SITE3 | Silphium terebinthinaceum Ell., non Jacq. | Silphium compositum var. reniforme | Asteraceae
|
| SITE | Silphium terebinthinaceum Jacq. | prairie rosinweed | Asteraceae
|
| SITRL | Silphium trifoliatum L. var. latifolium Gray | whorled rosinweed | Asteraceae
|
| SITRT | Silphium trifoliatum L. var. trifoliatum | whorled rosinweed | Asteraceae
|
| SITR7 | Silphium trifoliatum L. | whorled rosinweed | Asteraceae
|
| SITR4 | Silphium trilobatum L. | Sphagneticola trilobata | Asteraceae
|
| SIVE2 | Silphium venosum Small | Silphium compositum var. venosum | Asteraceae
|
| SIWA | Silphium wasiotense M. Medley | Appalachian rosinweed | Asteraceae
|
| SILPH | Silphium L. | rosinweed | Asteraceae
|
| SIMA3 | Silybum marianum (L.) Gaertn. | blessed milkthistle | Asteraceae
|
| SILYB | Silybum Adans. | milkthistle | Asteraceae
|
| SIGLL | Simarouba glauca DC. var. latifolia Cronq. | paradisetree | Simaroubaceae
|
| SIGL3 | Simarouba glauca DC. | paradisetree | Simaroubaceae
|
| SITU | Simarouba tulae Urban | aceitillo falso | Simaroubaceae
|
| SIMAR | Simarouba Aubl. | simarouba | Simaroubaceae
|
| SICA14 | Simmondsia californica Nutt. | Simmondsia chinensis | Simmondsiaceae
|
| SICH | Simmondsia chinensis (Link) Schneid. | jojoba | Simmondsiaceae
|
| SIMMO | Simmondsia Nutt. | goatnut | Simmondsiaceae
|
| SIMI6 | Simpsonia microcarpa (Sarg.) O.F. Cook | Thrinax morrisii | Arecaceae
|
| SICA7 | Simsia calva (Engelm. & Gray) Gray | awnless bushsunflower | Asteraceae
|
| SIEXP | Simsia exaristata Gray var. perplexa Blake | Simsia lagasceiformis | Asteraceae
|
| SIEX | Simsia exaristata Gray | Simsia lagasceiformis | Asteraceae
|
| SIFR | Simsia frutescens Gray | Encelia frutescens var. frutescens | Asteraceae
|
| SILA11 | Simsia lagasceiformis DC. | annual bushsunflower | Asteraceae
|
| SISC2 | Simsia scaposa Gray | Encelia scaposa | Asteraceae
|
| SIMSI | Simsia Pers. | bushsunflower | Asteraceae
|
| SIAL5 | Sinapis alba L. | white mustard | Brassicaceae
|
| SIAR4 | Sinapis arvensis L. | charlock mustard | Brassicaceae
|
| SIIN8 | Sinapis incana L. | Hirschfeldia incana | Brassicaceae
|
| SIJU2 | Sinapis juncea L. | Brassica juncea | Brassicaceae
|
| SINI4 | Sinapis nigra L. | Brassica nigra | Brassicaceae
|
| SINAP | Sinapis L. | mustard | Brassicaceae
|
| SISP6 | Sinningia speciosa (G. Lodd.) Hiern | Brazilian gloxinia | Gesneriaceae
|
| SINNI | Sinningia Nees | sinningia | Gesneriaceae
|
| SILA23 | Sinocalamus latiflorus (Munro) McClure | wideleaf bamboo | Poaceae
|
| SINOC | Sinocalamus McClure | wideleaf bamboo | Poaceae
|
| SIIN18 | Siphonanthus indicus L. | Clerodendrum indicum | Verbenaceae
|
| SIFL2 | Siphonella floribunda (Gray) Jepson | Linanthus floribundus ssp. floribundus | Polemoniaceae
|
| SIDE6 | Siphoneugena densiflora Berg | hoja menuda | Myrtaceae
|
| SIPHO2 | Siphoneugena Berg | siphoneugena | Myrtaceae
|
| SIBR7 | Siphonia brasiliensis Willd. ex Adr. Juss. | Hevea brasiliensis | Euphorbiaceae
|
| SIDI6 | Siphonoglossa dipteracantha (Nees) Heller | Siphonoglossa pilosella | Acanthaceae
|
| SIGR5 | Siphonoglossa greggii Greenm. & C.H. Thompson | Gregg's tubetongue | Acanthaceae
|
| SILO2 | Siphonoglossa longiflora (Torr.) Gray | longflower tubetongue | Acanthaceae
|
| SIPI | Siphonoglossa pilosella (Nees) Torr. | hairy tubetongue | Acanthaceae
|