LEAF AND PETIOLE MICRO-ANATOMICAL DIVERSITIES IN SOME SELECTED NIGERIAN SPECIES OF COMBRETUM LOEFL.: THE SIGNIFICANCE IN SPECIES IDENTIFICATION AT VEGETATIVE STATE

Opeyemi Philips AKINSULIRE 1*, Olaniran Temitope OLADIPO 1, Oluwabunmi Christy AKINKUNMI 2, Oladipo Ebenezer ADELEYE 1, Kole Fredrick ADELALU 1,3
1 Department of Botany, Obafemi Awolowo University, Ile – Ife, Nigeria
2 Department of Microbiology, Federal University of Technology, Akure, Nigeria
3 Biosystematics and Evolution Laboratory, Chinese Academy of Science, Wuhan Botanical Garden, China

Leaf and petiole samples of four Combretum Loefl. species which were identified in the Herbarium (IFE) were investigated anatomically in search of stable taxonomic micro-anatomical attributes to improve our knowledge of identification of members of the genus. Anatomical characters; in particular, upper and lower cuticle and epidermal structures, fibre structure, vascular architecture, petiolar outline and trichome micro-morphology are good taxonomic tools to identify the taxa. The invariable uniseriate to multiseriate upper and lower epidermis; the absence of trichome in the petiole and the presence of branched trichome in the mid-rib region of C. zenkeri P. Beauv delimit the taxa. Variations in vascular architecture can be used to identify the taxa while some other anatomical features in the genus suggest great taxonomic affinities. However, the artificial key, which was constructed using stable taxonomic characters, is a reliable taxonomic tool for proper identification of the four species and which can as well be employed in separating each of the taxa from their close relatives. A detailed anatomical study of leaf structures of the Nigerian Combretum species may provide an invaluable tool for determination and identification of the four taxa studied thereby assisting in promoting quality assurance in the genus.