Abstract:The morphological characters such as size, shape, apertures, furrow, exinestratification, tectum pattern, etc. of pollen in seven species and one variety of the genusPueraria DC. (P. lobata, P. lobata var. Montana. P. thomsonii, P. alopecuroides, P. calycina,P. edulis, P. Peduncularis and P. phaseoloides) from China were studied under LM andSEM; two species and one variety of them were studied under TEM. The results are as follows.Under LM, the tricolporate of a single pollen grain is subspherical, spherical andwide elliptical in shape in equatorial view, and 3-lobed circular in polar view. The sizeof pollen grain is generally constant; the length of polar axis is 18-34μm, mostly25.5- 28.5μm.Under SEM, the oramantation of the pollen grain may be divided into three types: (Ⅰ)perforate type, the diameter of pollen grain is generally less then or nearly equal to that ofmurus, no or only a few granules are present in the lumina; (Ⅱ) fine reticulate type, the diameter of lumina is nearly equal to or slightly smaller than that of murus, and there aregranules in the lumina, (Ⅲ) coarse reticulate type, the diameter of most lumina is longerthan that of murus and with numerous granules in the lumina. The pore type are: (1) thepore with membrane or sometimes operculum; (2) pore membrane often appears as bridgecrossing the colpus.Under TEM, the pollen grain has complete exine with sexine (including tectum,columella, foot layer) and nexine. The sexine is thicker than nexine, the tectum is thick,the foot layer is extremely thin.The morphological characters are varied within subsection or between subsections. Vander Maesen put P. lobata complex (including P. lobata var. lobata, P. lobata var. montana,and P. lobata var. thomsonii), P. alopecuroides, P. calycina and P. edulis under the samesubsection. Chen Zhongyi considered the P. lobata var. thomsonii as a species.It is suggested that the evolutionary trend of the ornamantation of the pollen grain is fromsubpunctate type to fine reticulate, then to course reticulate type. It corresponds withFerguson's idea. According to the oramantation Pueraria lobata is a more primitive species,and P. lobata var. montana and P. alopecuroides are closely related to P. lobata; all of thembelong to perforate type. P. thomsonii and P. edulis belong to fine reteculate type, while P.calycina to coarse reteculate type and they seem to be more evolutionary species in thesubsection.P. peduncularis and P. phaseoloides have coarsely reticulate ornamantation; the aperturemembrane is generally indistinct and the equatorial colpus bridge is usually present. There aremuch differences from the subsection mentined above.
