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Taxonomic value of leaf epidermal markers in discriminating some medicinal tree species of Apocynaceae Juss.
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1  Department of Forest Production and Products, University of Ibadan, Nigeria


Apocynaceae is a useful family comprising of trees notable for different medicinal remedies. Consequent to their importance vis-à-vis scarcity in the forest, they are being sold in various Nigerian markets by herb sellers mostly in sterile and fragmentary forms. Hence, the medicinal plants are subjected to adulteration and substitution. Frequently, identification of the plants by users are basically via floristic markers, which are not readily available for such purpose. It therefore becomes pertinent to carry out the taxonomic revision of these trees to provide additional markers that will contribute to their effective identification for correct use. Various documentations have been made on members of apocynaceae and are properly placed on their respective taxa using epidermal traits. However, such information is scarce for Alstonia boonei, Holarrhena floribunda, Rauvolfia vomitoria, Thevetia nerifolia and Vocanga africana. This study therefore aimed at providing epidermal taxonomic markers that could be employed in delimiting the species as alternative when the fruit or floral parts are wanting. Leaf epidermis of five (5) species of apocynaceae representing 5 genera were studied under a Biological microscope with camera attachment. Data obtained were statistically analyzed. Epidermal cell was Penta or hexagonal in A. boonei and V. africana. Stomatal length varied from 20.88 µm (R. vomitoria) to 25.92 µm (T. nerifolia) and 18.96 µm (R. vomitoria) to 29.28 µm (V. africana) on the abaxial and adaxial layers respectively. All the epidermal characters on the adaxial layer were significantly different (p<0.05) among the species. Anticlinal walls were sinuated in H. floribunda and T. nerifolia while in R. vomitoria, it was straight to wavy. V. africana and A. boonei anticlinal walls were straight. This study represents the first account of epidermal characterization of the members of apocynaceae in Nigeria and are of taxonomic importance in setting boundaries among the species.

Keywords: Apocynaceae; Medicinal trees; taxonomic character; leaf epidermis
Comments on this paper
Olayinka Otunla
Very informative piece, well researched
Thanks so much for your comment

Oluwadamilola Ogundipe
Very educative and a a great baseline study to the research field. A comprehensive research...good job

Awoniyi bolanle
Well research