fot. byn.

Pollen from 14 species of Haworthia (Family Liliaceae, Tribe Aloineae) were examined with the electron (scaning and transmission) and light microscopes. Optical microscope studies revealed a pollen size that depends upon the chromosome number; pollen grains of the diploid species are smaller than those from polyploid plants. Pollen grains are monoaperturate and, under the SEM, all 14 species display a perforated tectum. However, the proximal exine surface is smooth in some species and rough in others. The SEM study showed an identical tripartite ektexine composed of the foot layer, columellae and tectum in all species. The intine beneath the foot layer, however, exhibits certain variations in thickness. No differences in pollen fine structure of diploid and euploid plants could be detected. The need for further studies on the pollen ultrastructure was emphasized.