Thyrsanthella difformis (Walter) Pichon. Climbing Dogbane. Phen: May-Jul; Jul-Sep. Hab: Dry-mesic to mesic upland forests and woodlands, bottomland and riparian forests, moist prairies, flatwoods, swamps, marshes, old fields, roadsides. Dist: DE south to n. peninsular FL, west to e. TX, north in the interior to MO and IN.
ID notes: Very variable in leaf size, with leaves up to 14 cm long and 8 cm wide, but usually much smaller and proportionally narrow than that. The leaves are often about the size and shape of Gelsemium leaves; fresh material is easily distinguished by its milky sap.
Origin/Endemic status: Endemic
Syn: = Fl5, K4, Ok, WH3, Livshultz et al (2007); = Forsteronia difformis (Walter) DC.; = Trachelospermum difforme (Walter) A.Gray – Ar, C, F, G, GW2, Il, K1, K2, Mo2, RAB, S, Tn, Tx, Va