Abstract:

The leaf lower epidermal characteristics of 21 species of Polygonum sect. Aconogonon and Koenigia from China were observed under light microscope(LM).Three main types of leaf lower epidermal micro-morphology could be recognized in the present paper;(1)The stomata are anomocytic; the shape of the leaf epidermal cells is irregular,and the anticlinal walls are undulate;(2)The stomata are anomocytic or nontypical anisocytic; the shape of the leaf epidermal cells is irregular or polygonal,and the anticlinal walls are straight to curved and undulate;(3)The stomata are anisocytic; the shape of the epidermal cells is polygonal,and the anticlinal walls are straight to curved.The present data indicated that the sect. Aconogonon is a natural group with highly uniform stomata.The results of this study didn’t support to ascribe P. forrestii Diels and P. nummularifolium Meissner into the genus Koenigia.The generic status of Knorringia is supported,and P. polystachyum and P. pinetorum should be retained in sect. Aconogonon.

Key words: Polygonum section Aconogonon, Koenigia, leaf lower epidermis, China