Palynological studies of the genus <i>Combretum</i> Loefl. from Akwa-Ibom State, Nigeria

Abstract

Variations in pollen morphology were investigated in nine (9) common species of Combretum found in Uyo metropolis, Akwa-Ibom State, Nigeria. The species included Combretum bracteatum, C. calobotrys, C. dolichopetalum, C. hispidum, C. mannii, C. mooreanum, C. platypterum, C. racemosum and C. zenkeri. The pollen samples were acetolysed and examined under light microscope. The investigation showed that the pollen grains were all heterocolpate and circular in shape. Sculpturing was psilate or scabrate and pollen shape class was either sub-prolate, oblate-spheroidal or prolate spheroidal. Among the 9 species of Combretum, maximum polar dimension (34.41-44.40 μm) was found in C. platypterum whereas minimum polar dimension (21.09-38.85 μm) was noted in C. racemosum and C. zenkeri. The equatorial dimensions were highest (29.97-34.12μm) in C. mooreanum while the lowest equatorial dimension (17.76-31.08 μm) was observed in C. zenkeri. Pore diameters were highest (8.88-15.54) in C. calobotrys and C. platypterum and least (5.55-13.32) in C. bracteatum, C. racemosum and C. zenkeri. There was no significant difference in exine thickness among the species.