- twining perennial with milky sap
- stems not high-climbing, often becoming knotted on branches of thorny shrubs
- leaves opposite, narrowly arrow-shaped, less than 1 inch long
- flowers on short pedicels from leaf axils, with 5 very slender yellowish-green petals
- once thought to be endemic to South Texas, but recently discovered in Nuevo Leon
- blooms in March and early April; ID difficult later in season
