A palynological study of the genus helleborus (ranunculaceae)

Abstract

The pollen of 18 collections representing 1 I species of Helleboriis has been examined in Lhl and SEhl, and a selected group in TELL The pollen is 3-colpate and has a finely or coarsely reticulate tectum in which the muri are colliculate, or, more rarely, a complete tectum which is sparsely colliculate and sparsely punctate. The three tectalmorphs probably represent a progression in the -degree of completeness- of the tectum and they are clearly related. They are, however, distinct from each other, and no intermediate forms bvere found that might have compromised the separation of the finely reticulate and coarsely reticulate tecta. The three tectalmorphs have an unequal distribution, the complete tectum was found in only one species (H. niger), the finely reticulate in four species, and the coarsely reticulate in six species. For the most part the pollen data reinforce existing infrageneric alignments. Palynologically, Helleborirs can be distinguished from all remaining members of the Ranunculaceae, the vast majority of which have a spinulose and punctate/perforate tectum. © 1983, Taylor & Francis Group, LLC. All rights reserved.