Metastelma trichophyllum (L.O. Williams) W.D. Stevens Metastelma trichophyllum (L.O. Williams) W.D. Stevens in Phytologia 64(5): 335. 1988 sec. Juárez-Jaimes & al. 2007≡Cynanchum trichophyllum L.O. Williams in Fieldiana, Bot. 32(4): 41. 1968 syn. sec. ???