Taxonomic significance of leaf morpho-anatomical markers in identifying Ficus exasperata Roxb., Ficus mucuso Welw. ex Ficalho and Ficus thonningii Blume in Nigeria

Indigenous Ficus species are well noted for ethnomedicinal uses in Nigeria. Among the available species, Ficus exasperata, Ficus mucuso and Ficus thonningii are very germane to traditional herbal practitioners. Upon this basis, various parts such as leaves, barks and roots are frequently collected for medicinal purposes. Literature has shown that the identification of most of the Ficus species in Nigeria is based on the characterisation results generated by taxonomists several decades ago. Adequate and recent taxonomic evidence is needed for the discrimination and better understanding of the affinities among medicinally important and closely related species. Although macro morphological analysis has hitherto provided clues to differentiating the taxa by a common layman, however, combining it with leaf epidermal characters would produce a better predictive delimitation of the taxa. This study, therefore, investigated the Morpho-Anatomical markers for identifying Ficus exasperata, Ficus mucuso and Ficus thonningii.

Leaves samples were collected from the lower canopy portion of the tree species located in the University of Ibadan Campus, Nigeria. Specimens were prepared, analysed for morphological and epidermal characters following standard methods.

The result shows that Ficus exasperata and Ficus mucuso shared appreciable morphological similarities, which are taxonomically different from Ficus thonningii. In terms of the anatomical delimitation, F. mucuso was differentiated from the other two species by having actinocytic stomata on the abaxial layer of the leaf. Whereas, F. exasperata lacks stomata on the adaxial layer. Epidermal cell shape is polygonal for all the species while the trichome present is stellate, foliform and papillary respectively for F. exasperata, F. mucuso and F. thonningii on the abaxial layer.

Based on the identified taxonomic evidence observed in this study, leaf anatomical markers could provide discriminatory information for the taxa even when the plants are in fragmentary forms.