Pollen morphology of 25 species in the family Apocynaceae from the Adolpho Ducke Forest Reserve, Amazonas, Brazil

The Apocynaceae family consists of approximately 4555 species worldwide, distributed among 415 genera. In Brazil, this family is represented by 90 genera and 850 species. The Adolpho Ducke Forest Reserve, part of the Instituto Nacional de Pesquisas da Amazonia (INPA) since 1963, comprises 100 km(2) of non-isolated continuous primary forest, and 40 species and 16 genera of Apocynaceae have been recorded in this area. Pollen grains, collected from flower buds and/or flowers of voucher specimens deposited at the INPA Herbarium collection, were processed using the acetolysis method, and measured, described and photographed by light microscopy and scanning electron microscopy. The study included 25 Apocynaceae species distributed among 14 genera. The pollen grains were porate to colporate, with exine ornamentation varying from psilate or scabrate to microreticulate. Other morphological characteristics were pores with granules at the base of the annulus in Odontadenia, a distinct margo forming arches around the colpus in Geissospermum, and the presence of a thick endocingulum in the equatorial region in species of Tabernaemontana.