Morphologicaand Phytochemical Characterization of Cassiinae in Nigeria

Abstract

Background and Objective: Cassiinae is the largest subtribe that constitutes the tribe Cassieae (Caesalpiniodeae) in the Fabaceae family. The autonomy and classification of the generic categories (Cassia, Senna and Chamaecrista) in the subtribe were established in this work using multiple character variations obtained from anatomical, morphological and phytochemical evidence to determine the taxonomic relationship among 10 studied taxa. This has led to the production of a reliable identification key. Materials and Methods: A total of 45 vegetative and reproductive characters, 13 anatomical and 13 phytochemical characters were qualitatively and quantitatively evaluated. The characters obtained were subjected to numerical and principal component analysis following Sokal and Sneath principles. The phenetic relationship among the groups was determined by hierarchical cluster analysis using the R programme. Results: A dendrogram containing three groups and a few subgroups representing the 10 taxa was produced. Cluster 1 comprises Cassia fistula and Cassia sieberiana. Cluster 2 contains only Chamaecrista rotundifolia while cluster 3 includes Senna alata, Senna hirsuta, Senna occidentalis, Senna siamea, Senna polyphylla, Senna obtusifolia and Senna surattensis. The resultant delimitation into 3 groups is a result of the combination of OTU of gross morphological and phytochemical characters during numerical analysis. The two-dimensional model of principal component analysis used highlighted shared characters of taxonomic significance that support delimitation of members of the group. Conclusion: This study affirms that morphological features are not sufficient enough but indispensable in the identification and classification of a clade.