Palynological studies on five species of Asteraceae

Abstract

Palynological studies on five species of the family Asteraceae namely Guternbergia nigritiana, Emilia praetemissa, Vernonia guineensis, Lagera pterodonta and Chromolena odorata was carried out. Results
obtained from this investigation showed that the pollen shape is spheroidal in G. nigritiana, E. praetermissa and C. odorata while it is elliptic in V. guineensis and L. pterodonta. The pollen aperture is
porate in all except in L. pterodonta where it is elliptic. The pollen wall is echinate in all except in C. odorata where it is smooth. The general appearance of the pollen grains is circular in G. nigritiana, E.
praetermissa and C. odorata but longer than wide in V. guinensis and L. pterodonta. It is therefore likely that the nature of the pollen grains in these species could be an evolutionary modification often
inherited to determine the mode of pollination and thereby perpetuate a particular group of plants. The similarities in structure showed interspecies relationships and reasons for them to be in the same
family while the differences in structures showed reasons for them to exist as distinct species.