Abstract: Pollen morphology of three species in the genus Maharanga and 12 species in the genus Onosma , belonging to the family Boraginaceae, was examined by means of light microscope and scanning electron microscope. Pollen grains of the genus Maharanga are dumbbell-shaped or cocoon-shaped, medium-sized, P/E 1.6--1.67 ratio, tricoporate with lalongate ora,and spinulate,while those of the genus Onosma are subprolate or ovoid, P/E 1--1.23 ratio, tricolporate or trisyncolporate with lolongate ora, rugulate-microgranulate or tuberculate. The pollen morphology supports the separation of the genus Maharanga from the genus Onosma (sensu lato). Noteworthily, the three colpi of syncolporate pollen in some members of the genus Onosma converge in one pole or even two poles.

Key words: Pollen morphology, taxonomy, Maharanga, Onosma