Pollen morphology of <i>Prototulbaghia Vosa</i>: A comparative palynological study of the Southern African Alliaceae.

Abstract

The Southern African Alliaceae Borkh. is represented by four genera (Allium L., Nothoscordum Kunth, Tulbaghia L. and Prototulbaghia Vosa) and 28 species. The pollen morphology of the endangered monotypic genus Prototulbaghia has not been described before. A comparative study of the pollen morphology of Prototulbaghia siebertii Vosa, Nothoscordum borbonicum Kunth, Tulbaghia simmleri P.Beauv. and T. violaceae Harv. is presented in this article. Scanning electron microscopy, as well as light microscopy, were used to examine the pollen. The pollen morphology of the species can be described as perprolate and monosulcate, and the surface sculpture as reticulate and heterobrochate. However, the pollen of Prototulbaghia siebertii displays a unique characteristic as the grains are folded in their breadth with the tips touching, hence causing the grain to display a triangular and disulcate appearance. It might be possible to ascribe this fold to the process of harmomegathy or a still unknown event that occurs during the development of the pollen grain. This phenomenon should be further investigated to determine the cause of folding and whether it is a unique taxonomic characteristic of this genus, and if it could be of evolutionary significance for the Alliaceae.