Typical tree slelction and random sampling were applied for systematic studies of individual variation of gutta-percha content in samaras of Eucommia ulmoides and the correlations between the characters of samara containing gutta-percha and several macroscopic properties. Integrated extraction was applied for gum content tests. The result showed that characteristics of samara of different clones, its gutta-percha content characters such as the length, width, thickness of samara, the shape index (ratio of length to width) ,the weight of kilo-seed, gutta-percha content, rate in pericarp, seed an...