Microscopic studies on the structural feature of th e leaf of plants in tribe Areae found in Zhejiang Province were carried out for t he purpose to provide valuable informations for the classification and identific ation of medicinal plants of tribe Areae currently used as ther apeutic remedies . Leaves of 45 samples from 11 species, 6 varieties and 1 form of the tribe Areae found in Zhejiang were examined under light microscope, and their microscopic characteristics, such as shape and size of epidermal cell; palisade ratio; locat ion and type of stoma; stomatal index; shape, size and location of calcium oxala te crystals and shape of raphide sac cell in mesophyll were compared. The micro sc opic characters of the plants under study were found to vary greatly between spe cies, but were generally similar among the same species. The most outstanding m icroscopic characters that may differentiate one species from the other were car efully examined, compared, and tabulated for reference. The diagnostic features found were considered to be of value for taxonomy in the following aspects: (1) These features can be used to distinguished among species in tribe Areae (2) T he state of characters, for instance, calcium oxalate druse and stoma, are of gr e at value for the division of subtribes or genera in tribe Areae. (3) Th ey are helpful for the reasonable taxonomy of some taxa in tribe Areae