Studies on the micromorphology of leaf epidermis in Cynanchum (Asclepiadaceae) from China under environmental scanning electron microscope (ESEM).

The micromorphology of leaf epidermis of 13 species and 1 variety in Cynanchum from China were examined by environmental scanning electron microscope (ESEM) .The results showed that there were high diversity in the micromorphology of leaf epidermis of Cynanchum.The shapes of leaf epidermal cells in Cynanchum were usually polygonal or irregular.All the abaxial epidermis had stomata,and most of the shapes of the stomata were not sunken.The inner margin of the outer stomatal rim was nearly sinuolate.Many species of Cynanchum had glabrous leaves and thick cuticular membrane on leaves.A few species are distinctively different from others in their size of stomata and ornamentation of cuticular membrane.It was accepted to put C.corymbosum,C.insulanum and C.insulanum var.lineare into Section Endotropis.