Unique Pollen Types in the Caesalpinioideae (Leguminosae)

Abstract

In the legumes several pollen types were encountered during a survey of the Caesalpinioideae that were previously unknown or poorly known for the subfamily: Viscin threads (Jacqiteshuberia). periporate pollen (Hardirickia, ColopAospermitm), diporate pollen with a single continuous colpus (Dirparqiretia), tetracolporate pollen (Ceraronia), and pollen tetrads (Afielia, Diptychandra).

An exine architecture model for viscin threads

“…Viscin threads are sporopollenin-containing, long, thin, flexible ropes basically located on the pollen surface and distally extended between neighbouring pollen tetrads or single grains. As known up to now, they, occur in most of the Onagraceae, in many Ericaceae, and only in few Caesalpiniaceae, therefore only in three unrelated angiosperm families (Skvarla et al 1978, Graham et al 1980. They consist of exine material and are in fact parts of the exine itself.…”

Pollen Morphological Studies of 10 Endemic Legumes From India.

“…is a unique type in Caesalpinioideae, only reported from an African genus Colophospermum Kirk ex J. Leonard and this condition is said to be a method of increasing contact between cuticular-dissolving enzymes of the intine and the stigmatic surface (Graham et al, 1980).…”

Notes on the exine ultrastructure of Onagraceae and Rhododendroideae (Ericaceae)

“…He deduces his model on the cxistance of columcllae, there arc however no typical columcllae 'in the investigated species of the Onagraceae and the Rhododendroideae. On the other hand the model seems to be correct for the Ceasalpinoideae (Graham et al 1980, Patel et al 1985. Although columcllac-like structures of sporopollenin particles, arranged in a beaded rope are sometimes found in the Onagraccac, they never possess typical columellae, if any columellae at all.…”