| Sergio C. de Sant'Ana |
Spermatophytes |
| Henry P. Sartwell |
Spermatophytes; Cyperaceae; Bryophytes; Algae; Characeae |
| Albert Schneider |
Algae; Lichens; Mycology |
| Irma Schnooberger |
Bryophytes |
| Wilfred B. Schofield |
Bryophytes |
| Arthur C. V. Schott |
Algae; Bryophytes; Spermatophytes |
| Carl A. Schwarze |
Mycology |
| George W. Scotter |
Spermatophytes; Bryophytes; Lichens |
| Fred J. Seaver |
Mycology; Discomycetes; Lichens |
| Augustine D. Selby |
Algae; Mycology |
| John A. Shafer |
Algae; Pteridophytes; Spermatophytes; Mycology; Bryophytes |
| Aaron J. Sharp |
Algae; Bryophytes; Mycology; Spermatophytes |
| Carleton A. Shurtleff |
Spermatophytes |
| Marcos Silveira |
Spermatophytes; Ecology of arborescent bamboos; systematic botany, plant ecology; flora of Southwestern Amazonia |
| John Kunkel Small |
Algae; Bryophytes; Pteridophytes; Spermatophytes; Lichens |
| Lyman B. Smith |
Spermatophytes; Pteridophytes; Lichens |
| Herbert H. Smith |
Spermatophytes; Bryophytes; Lichens |
| Albert C. Smith |
Algae; Spermatophytes; Pteridophytes; Bryophytes; Lichens |
| Richard Spruce |
Bryophytes; Pteridophytes; Spermatophytes; Lichens |
| Howard Stansbury |
Spermatophytes |
| William C. Steere |
Bryophytes; Lichens |
| Julian A. Steyermark |
Pteridophytes; Spermatophytes; Angiosperms; Bombacaceae; Bryophytes; Algae; Characeae; Lichens |
| Arlow B. Stout |
Bryophytes; Spermatophytes; Hemerocallis |
| William C. Sturgis |
Algae; Cryptogams; Mycology; Bryophytes; Spermatophytes |
| William S. Sullivant |
Bryophytes; Algae; Mosses; Spermatophytes |