Foundations Similarity index = a numerical index describing the similarity of two community samples in terms of their species content Similarity matrix = a square, symmetrical matrix with the similarity value of every pair of samples, if Q-mode, or species, if R-mode, in the data matrix The similarity matrix is the basis for all multivariate techniques depicting relationships among community sa...

Dimocarpus longan Lour. is an edible and traditional herb in China, commonly referred to as longon. An improved randomly amplified polymorphic DNA (RAPD) protocol was here developed in order to determine the geographical origins of D. longan samples collected from 5 provinces in the southern and southwestern areas of China, including Sichuan, Hainan, Fujian, Guangdong, and Guangxi. Generally, t...