Pollen morphology of the genus Lasianthus (Rubiaceae) and related taxa from Asia
亚洲茜草科粗叶木属及其相关属植物花粉形态研究

Pollen morphology of 16 Asian species including two subspecies and one variety of the genus La-sianthus and five species from five related genera was examined by light microscopy and scanning electron microscopy. Lasianthus Jack is eurypalynous. The pollen grains are small to medium in size and spheroidal or subprolate in shape, with a few being prolate. Pollen morphology is remarkably diverse, particularly in aperture and exine ornamentation. The apertures are usually (3-)4-(-5)-zonoaperturate, being porate and pororate. The number of apertures varies from three to five, with the majority of species being 3-4 zonoaperturate. The exine is usually perforate, finely reticulate or coarsely reticulate. Pollen data appear to be morphologically informative and useful for distinguishing among species of Lasianthus, and for elucidating the relationships among some species.