Anatomical Studies on the Stem and Leaf of Vernonia amygdalina Del, Cyanthillium cinereum (L.) H. Rob and Brenandendron donianum (DC.) H.Rob. in Southern Nigeria: Recent development

A light microscope was used to establish the taxonomic relationships of three species: Vernonia amygdalina Del. (Bitter leaf and Non-bitter leaf varieties), Cyanthillium cinereum (L.) H.Rob., and Brenandendron donianum (DC.) H.Rob. Anatomical evidence has recently led to plant species being separated from their families or genera and placed under a different taxon. In all of the taxa studied, the stem anatomy revealed a single layer of epidermis, 2-3 layers of collenchyma cells in V. amygdalina, and 4-5 layers in C. cinereum and B. donianum. In V. amygdalina and C. cinereum, the vascular bundles are organised in a concentric pattern, while in B. donianum, they are dispersed. The monocotyledonous plant’s dispersed vascular bundles and lack of pith, which is a distinguishing feature, are unusual in B. donianum and could be used for taxonomic purposes. The presence of bicollateral vascular bundles in B. donianum and open collateral in the other taxa investigated may be diagnostic. In all of the taxa studied, the anatomy of the midrib revealed a single layer of epidermis normally covered by a cuticle. In all of the taxa studied, the midrib has an oblong shape. A cap of 1-3 layers of thick-walled sclerenchyma in B. donianum and thin-walled parenchyma in C. cinereum and the two different taxa of V. amygdalina makes up the bundle sheath. V. amygdalina has 2–3 layers of collenchyma cells, while C. cinereum and B. donianum have 4-5 layers. In B. donianum, the vascular bundle is bicollateral, while in the other taxa studied, it is collateral. Variation in the form and organisation of vascular bundles in the midrib has taxonomic significance as well. The stem and leaf morphology of V. amygdalina (bitter leaf) and V. amygdalina (non bitter leaf) are identical, implying that the two taxa are the same species.

Author (s) Details

C. I. Kemka-Evans
Department of Biology, Alvan Ikoku Federal College of Education, Owerri, Imo State, Nigeria.

B. Okoli
University of Port Harcourt, Rivers State, Nigeria.

C. U. Nwachukwu
Department of Biology, Alvan Ikoku Federal College of Education, Owerri, Imo State, Nigeria.

M. Ikeanumba
Department of Biology, Alvan Ikoku Federal College of Education, Owerri, Imo State, Nigeria.

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