| Saccharum officinarum | Saccharum officinale |
| Salvia apiana | Audibertia polystachya, Audibertiella polystachya, |
| Samanea saman | Pithecellobium saman, Albizia saman |
| Sandoricum koetjape | Sandoricum indicum |
| Santisukia pagetii | Radermachera pagetii, Barnettia pagetii |
| Sapium sebiferum | Triadica sebifera |
| Saraca indica | Saraca asoca |
| Sauromatum venosum | Sauromatum guttatum |
| Schinus molle | Schinus huigan |
| Schinus polygamus | Schinus dependens |
| Schinus terebinthifolius | Schinus chichita, Schinus mucronulata, Schinus antiarthriticus |
| Schinziophyton rautanenii | Ricinodendron rautanenii, Ricinodendron viticoides |
| Schisandra chinensis | Kadsura chinensis, Maximowiszia chinensis, Maximowitschi japonica, Polycarpa maximowiczi |
| Schizolobium parahybum | Schizolobium excelsum |
| Schleichera oleosa | Schleichera trijuga |
| Schrebera alata | Schrebera argyrotricha, Schrebera gilgiana, Schrebera mazoensis |
| Scorpiurus muricatus | Scorpiurus subvillosus, Scorpiurus sulcatus |
| Senecio confusus | Pseudogynoxys chenopodioides |
| Senna artemisioides ssp. filifolia | Cassia nemophila |
| Senna artemisioides ssp. petiolaris | Cassia petiolaris, Senna phyllodinea, Cassia phyllodinea |
| Serenoa repens | Serenoa serrulata |
| Sesbania sesban | Sesbania aegyptica, Aeschynomene sesban, Emerus sesban, Sesban aegyptiaca, Sesbania confaloniana, Sesbania pubescens |
| Sesbania tripetii | Sesbania punicea, Daubentonia tripetii, Daubentonia punicea |
| Sicana odorifera | Cucurbita odorifera, Sicana atropurpurea |
| Sida carpinifolia | Sida acuta |
| Simmondsia chinensis | Simmondsia Californica |
| Sinocalycanthus chinensis | Calycanthus chinensis |
| Solanum mauritianum | Solanum auriculatum, Solanum verbascifolium var. auriculatum |
| Solanum muricatum | Solanum variegatum, Solanum guatemalensis |
| Solanum quitoense | Solanum angulatum |
| Solanum topiro | Solanum sessifliflorum |
| Solanum torvum | Solanum ficifolium |
| Sophora davidii | Sophora viciifolia |
| Sophora japonica | Styphnolobium japonicum |
| Sophora secundiflora | Sophora speciosa, Sophora sempervirens, Agastianis secundiflora, Calia secundiflora |
| Sophora tetraptera | Sophora grandiflora, Edwardsia grandiflora |
| Sophora velutina | Sophora glauca |
| Spondias dulcis | Spondias cytherea, Spondias purpurea, Spondias mombin |
| Stachytarpheta mutabilis | Stachytarpheta speciosa |
| Stauntonia hexaphylla | Rajania hexaphylla |
| Stemona sessilifolia | Roxburghia sessilifolia, Stemona erecta |
| Stemona tuberosa | Stemona acuta |
| Stephanotis floribunda | Stephanotis jasminoides |
| Stictocardia beraviensis | Ipomoea beraviensis, Argyreia beraviensis |
| Stictocardia tiliifolia | Stictocardia campanulata |
| Stictocardia woodii | Ipomoea woodii, Stictocardia laxiflora var. woodii |
| Strelitzia alba | Strelitzia augusta |
| Strelitzia juncea | Strelitzia reginae var juncea |
| Strumaria unguiculata | Hessea unguiculata |
| Strychnos madagascariensis | Strychnos burtonii, Strychnos dysophylla, Strychnos innocua ssp. dysophylla |
| Strychnos spinosa | Strychnos buettneri, Strychnos cardiophylla, Strychnos carvalhoi, Strychnos cuneifolia, Strychnos dulcis, Strychnos courteti |
| Syzygium aromaticum | Eugenia caryophyllata |
| Syzygium australe | Eugenia australis, Eugenia myrtifolia |
| Syzygium cumini | Eugenia cumini, Eugenia jambolana, Eugenia obovata, Myrtus obovata, Syzygium jambolana, Syzygium obovatum |
| Syzygium jambos | Eugenia jambos |
| Syzygium javanicum | Syzygium samarangense |
| Syzygium luehmannii | Eugenia luehmannii |
| Syzygium moorei | Eugenia moorei |
| Syzygium oleosum | Eugenia coolminiana, Syzygium cooliminianum |
| Syzygium paniculatum | Eugenia paniculata |
| Syzygium samarangense | Eugenia javanica |