| Family | Scientific Name | Common Name | Habitat | Distribution | Image |
|---|
| Apocynaceae | Chthamalia biflora | Star Milkvine, Two-flowered Milkvine | Grasslands and woodlands. | OK south to se. TX. wc. TX, se. NM. | 
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| Apocynaceae | Chthamalia brevicoronata | Shortcrown Milkvine | In grasslands on tight sandy or silty substrates of woodlands, thornscrub, and fields in the lower Rio Grande Plain. | S. TX (Brooks, Duval, Hidalgo, Kenedy, Starr, Webb, and Zapata counties). | |
| Apocynaceae | Chthamalia cynanchoides | Prairie Milkvine | Dry sandy woodlands, openings, and edges. | Sw. AR and OK south to nw. LA and e. TX. | 
|
| Apocynaceae | Chthamalia parviflora | Smallflower Milkvine | Dunes, oak mottes, open sandy areas. | S. TX south to ne. Mexico (COA, NLE, TAM). | 
|
| Apocynaceae | Chthamalia pubiflora | Trailing Milkvine, Sandhill Spinypod | Sand ridges, longleaf pine 'yellow sand' sandhills. | E. GA (Jones & Coile 1988) south to c. FL. | 
|
| Apocynaceae | Chthamalia radiata | Falfurrias Milkvine | Thornscrub, in rocky and clayey soils on low hills or plains. | Endemic in s. TX (Rio Grande Plains) (Brooks, Hidalgo, and Starr counties). | 
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