Comparative Anatomy of Abrus Adanson Species in Parts of Tropical West Africa

Comparative anatomical studies of three Abrus Adanson species (A. precatorius, A. pulchellus and A. canescens) and a new collection identified as Abrus sp. were undertaken by simple microtomy. Parts of each species (seed, stem, root, leaf, pulvinus and petiole) were sectioned after fixation and wax embedding with a LEITZ 1512 rotary microtome at 20 to 24 μm thickness and observed with a LEITZ DIAPLAN photomicroscope. The seed coat in the species possesses five distinct layers, which varied in thickness. Similarities were observed in the arrangement, differentiation and distribution of cells and tissues in the investigated organs with characteristic pubescence in all organs of A. canescens. However, the number of layers of these cells and tissues (collenchyma, pericyclic parenchyma, sclerenchyma, pith parenchyma and the vascular cells) occasionally differed and could be harnessed for taxonomic purposes. The study aims at providing detailed comparative anatomical information for the genus, which is hitherto unavailable among the West African species. These will complement the morphological descriptions, which always overlap.