| Spermacoce villosa Sw., 1788 |
| Spermacoceae Bercht. J. Presl, 1820 |
| Staelia Cham. & Schltdl., 1828 |
| Staelia scabra (C. Presl) Standl., 1931 |
| Stenaria (Raf.) Terrell, 2001 |
| Stenaria mullerae (Fosberg) Terrell, 2001 |
| Stenaria nigricans (Lam.) Terrell, 2001 |
| Stenaria nigricans var. gypsophila (B.L. Turner) Terrell, 2001 |
| Stenaria nigricans var. nigricans (Lam.) Terrell, 2001 |
| Stenaria rupicola (Greenm.) Terrell, 2001 |
| Stenaria sanchezii Lorence, 2009 |
| Stenaria umbratilis (B.L. Rob.) Terrell, 2002 |
| Stenaria umbratilis subsp. brevipedicellata (Terrell) Borhidi, 2012 |
| Stenaria umbratilis var. brevipedicellata Terrell, 2001 |
| Stenostomum C.F. Gaertn., 1806 |
| Stenostomum aromaticum (Cast.-Campos & Lorence) Borhidi, 1995 |
| Stenostomum lucidum (Sw.) C.F. Gaertn., 1806 |
| Stenotis Terrell, 2001 |
| Stenotis arenaria (Rose) Terrell, 2001 |
| Stenotis asperuloides (Benth.) Terrell, 2001 |