Pollen morphology of Cassia s.l. (Leguminosae) and its taxonomic implications (Thai)

Abstract

Pollen morphology of 12 taxa of Cassia s.l. (Leguminosae) was investigated to determine its taxonomic significance by means of light and scanning electron microscope. The pollen is monad, radially symmetrical, isopolar, small to medium sized and tricolporate. Three pollen types are recognized based on apocolpium and mesocolpium exine sculpturing. Cassia bakeriana-type contains nine species, which are characterized by similar apocolpium and mesocolpium exine sculpturing, Senna garrettiana-type has different apocolpium and mesocolpium exine sculpturing and contains one species and Cassia fistula-type which is characterized by two species. Apocolpium is either similar or different from mesocolpium exine sculpturing. Pollen data does not support morphological evidence for separation of the Cassia s.l. into Cassia s.s. Chamaecrista and Senna as in the recent classification.