| Family | Scientific Name | Common Name | Habitat | Distribution | Image |
|---|
| Rubiaceae | Spermacoce glabra | Smooth Buttonweed | Moist shores, bottomlands, riverside drawdowns, rocky riversides in the mountains, disturbed areas in the Coastal Plain. | C. MD, s. OH, c. IN, c. IL, MO, and e. KS south to s. SC, Panhandle FL, s. AL, s. MS, LA, and e. TX. Perhaps only introduced in some parts of our area; see Wieboldt et al. (1998) for discussion. | 
|
| Rubiaceae | Spermacoce keyensis | Florida Buttonweed | Pinelands. | S. FL; West Indies. Reported for s. TX (Correll & Johnston 1970). | 
|
| Rubiaceae | Spermacoce ocymoides | | Wet pine flatwoods, floodplain forests. | FL, AL, MS, south through the New World tropics. | 
|
| Rubiaceae | Spermacoce remota | Woodland Buttonweed | Wet hammocks, bottomland forests, marshes. | Sw. GA, s. AL, and FL; Central America, South America, and the West Indies. | 
|
| Rubiaceae | Spermacoce tenuior | | In clay soils along creeks. | S. TX south through Mexico and Central America to South America. Reported from sw. GA and MS (Kartesz 1999, 2010) {IDs need checking; seems a bit unlikely}. | 
|
| Rubiaceae | Spermacoce tetraquetra | Pineland Buttonweed | Pinelands, hammocks, disturbed areas. | S. FL; West Indies; s. Mexico and Central America. | 
|