POLLEN MORPHOLOGY OF PERIPLOCA (PERIPLOCACEAE)

The pollen morphology of all 13 species of Periploca L. was studied. A ll the species are characterized by pollen grains arranged in tetrads. The arrangement of the grains may be rhomboidal, decussate or linear. Linear tetrads were only observed in P. acuminata Rahman & Wilcock, P . sepium Bunge and P. aphylla Decaisne. The exine is smooth. Exine str ucture consists of an outer, homogenous stratum (tectum) subtended by a granular stratum. Except for small differences which may occur betwe en species in pollen size, the pollen is uniform in morphology.