Important Morphological Characters in Several Species of Cassiinae (Leguminosae) in South-Western Nigeria

Abstract

Macromorphological characters of some species of Cassia L. emend. Gaertner, Senna Miller and Chamaecrista Moench occurring in South Western Nigeria were studied. The aim was to search for stable, distinctive and diagnostic characters for the identification of these genera and their species. Qualitative characters were noted and recorded while quantitative observations were done by the use of a metric ruler and the measurements were taken to the nearest centimeters. The habit ranges from all shrubs in Senna, shrubs and herbs in Chamaecrista while the Cassia species studied are all trees. The shape of the leaflet apex varies in both Senna and Cassia species, while it is distinctly mucronate in Chamaecrista genus. Occurrence of foliaceous stipule in the genus Chamaecrista clearly separates it from Senna and Cassia, which are completely exstipulate. In general, other characters such as number of leaflet pairs, length and width of leaflets, leaflet base, and number of leaflets lateral nerves revealed generic distinctions. Others include the degree of hairiness in sepals, petals shape, types of inflorescence, fruit shape and fruit length. The attributes that delimits the species are mainly quantitative. The results of this investigation suggest macromorphological characters that clearly enhance the taxonomy of these genera and their species and they can be subsequently employed in their delimitation.