The success rates of attachment of two twining lianas Ipomoea phillomega (Vell.) House (Convolvulaceae) and Marsdenia laxiflora Donn. Sm. (Asclepiadaceae) were compared. Ipomoea phillomega liana with relatively unspecialized shoot architecture was found to have a lower success rate than M. laxiflora a liana with specialized photsynthetic and twining shoots. The relatively lower success rate of I. phillomega is due to its reduced ability to remain attached to very thin supports (<7mm in dimater).