Character of Leaf Epidermis and Their Systematic Significance of Daphne and Wikstroemia (Thymelaeaceae)

Fifty six species (varieties) of Daphne, forty five species (varieties) of Wikstroemia and twelve species of outgroups from Thymelaeaceae, with ten phenotypic characters were selected, to study the leaf epidermal microfeatures by using light microscopy, Results reveal that Daphne and Wikstromia are consistent in most of leaf features. The epidermal cell are polygonal and irregular in shape. The patterns of anticlinal wall are straight, curved and U shape. The cell sizes range in 30-40μm × 10-20μm. Some species have singly hair on surface. Stomatal distribution is random, size range in 20-36μm × 17-25μm, most are broadly elliptical and narrowly elliptical, stomatal frequency are 100-250S/mm2, and the anomocytic stomatal type is dominate. It is apparently that many stomatal and epidermal features in Daphne and Wikstromia are crossed, and no distinguishable features are suitable for separating this two genera. Results from epidermal characters analysis don’t support monophyletic status of Daphne and Wikstroemia. Eriosolena should not be include in the genus Daphne as the special papillae only found in Eriosolena composita rather than in other genera of Thymeleaceae. In compare with other genera, Rhamnoneuron, Eriosolena, Stelleropsis, Daphnopsis and Edgeworthia in Thymelaeoideae, Daphne and Wikstroemia might be derived and originated latter based on the stomatal features.