Numerical taxonomic study of some euphorbiaceae species within Ambrose Alli University Main Campus, Edo State, Nigeria

Abstract

Numerical taxonomic studies have been described as highly effective in plant classification and delimitation even in difficult cases. This study employed numeric taxonomic methods in studying different Euphorbiaceae species within Ambrose Alli University campus with the goal of identifying similarities and differences between different species within the family. Twenty-five species comprising thirteen genera were studied using thirty-five morphological characters which included plant habit, colour of leaf, fruit shape, presence of sap, pubescence of leaves, presence of three-cell ovary, and inflorescence type. Data generated from the different morphological characters were scored and converted to binary numbers used for generating clusters of the Operation Taxonomic Units (OTUs) according to their overall similar Euclidean distance. Using both single and complete linkage, dendrograms were drawn to illustrate the relationship among the species. The dissimilarity shown in the OTUs were split into two clusters, C1 and C2 each comprising 10 and 15 species respectively. Species within the same cluster had greater similarity than those in the other cluster. Amongst diverse findings from the study is a great affinity between Jatropha curcas and Jatropha tanjorensis, Alcornea laxifolia and Mallotus oppositifolius; Hevea brasilensis and Croton zambesicus; and Acalypha hispida and Alcalypha wikisiena. Great dissimilarity was observed between Riccinodendron heudelotti and Euphorbia milli. The results from this study have shown that there is great similarity, and at the same time variety and heterogeneity among the different species of Euphorbiaceae considered.

Keywords: Dendrogram; Euphorbiaceae; Numerical Taxonomy; Species