| Family | Scientific Name | Common Name | Habitat | Distribution | Image |
|---|---|---|---|---|---|
| Rubiaceae | Hexasepalum radula | Chrome ore piles and ballast, a waif. | Native of South America. |  | |
| Rubiaceae | Hexasepalum teres | Poorjoe | Dunes, sandy roadsides, glades, hardpans, other dry habitats. | MA, NY and WI, south to FL, TX, and CA, south through Mexico and Central America. |  |