Pollen morphology of 44 species and 2 varieties in the genus Polygonum (Polygonaceae) in China was examined by means of both light microscope (LM) and scanning electron microscope (SEM). Pollen grains are spheroidal or subspheroidal, prolate or subprolate, suboblate; 3-colpate, 3-colporate, pantoporate, pantocolpate. The ornamentation of exine is finely or coarsely reticulate, rugulate, granulate-perforate, microechinate-perforate or microechinate-foveolate under SEM.
Based on the characteristics ten pollen types are recognized and described, i. e. Aconogonon-type, Cephalophilon-type, Bistorta-type, Avicularia-type, Convolvulus-type, Sibiricum-type, Tiniaria-type, Fagopyrum-type, Amphibium-type and Persicaria-type. A key to the types is provided.
According to the pollen types, the authors disagree with Steward’s (1930) treatment which divided the genus into eight sections, and consider the division of the genus into eleven sections more reasonable.