Pollen Morphology of some Species of Rhamnaceae from West Bengal

Pollen morphology of 10 species and 2 varieties of Rhamnacequs taxa belonging to all the four tribes have been worked out. Pollen morphology of the family shows a tendency of evolution from basic morphoforms to the derived ones. Pollen grains of all the taxa investigated have been found to possess triangular or sub-triangular amb with three equatorial apertures situated at the angles (angulo aperturate). In Ziziphus xylopyrus the pollen grains are pororate and in rest nine species those are colporate with circular or lalongate endoapertures. Exinc ornamentation shows a gradual tendency from granulose to rugulo-reticulate or reticulate pattern. Palynological features have been evaluated in understanding the taxonomy of the family.