A numerical taxonomic study of Trema (Ulmaceae) from Togo, West Africa

The assignment of collections belonging to the genus Trema has been reasses sed using numerical taxonomy methods. Observation in the field in Togo, Wes t Africa, confirmed high phenotypic variation but not the previously assert ed lack of character concordance within the T. guineensis complex. This stu dy was carried out to assess the circumscription of taxa in the area. Dista nce between specimens was computed using the Cower's general coefficient of similarity and the non-parametric MODECLUS cluster analysis was used to di scover hew the specimens segregated. The existence of three clusters in the 158 specimen dataset using 44 morphological characters was suggested by MO DECLUS. Canonical discriminant analysis supported the recognition of those three clusters using 40 morphological characters. Classificatory discrimina nt analysis showed that all specimens except one are identified correctly b y the discriminant function. We suggest that three species be recognized in Togo and the neighboring countries: T. orientalis, T. africana, and T. nit ens. A key to the species is included and the advantages of the method sugg ested here are discussed.