Pollen Morphology of 13 Chinese Species of Polygonatum and Its Systematic Significations

In this paper,pollen morphologies of 13 species of Polygonatum Mill.were investigated under LM and SEM.All of the species except P.cyrtonema,P.filipes,P.sibiricum,P.zanlanscianense examined under LM were reported for the first time.P.sibiricum,P.roseum and P.ginfoshanicum examined under SEM were reported for the first time.The results indicated that pollen grains of Polygonatum were characterized by various shapes,and the exine ornamentation was a character of complex column structure.The exine ornamentation can be divided into five types;verrucate,verrucate-perforate,perforate reticulate and reticulate-verrucate.The evolutionary trend was infered as follows: perforate type → verrucate-perforate type →verrucate type;perforate type →reticulate-verrucate type → reticulate type.The pollen grains of 13 species were analyzed primarily,which provided some useful information for systematic studies of the genus Polygonatum.