Taxonomic Studies On Some V16'na Savi Species (Leguminosae - Papilionoideae)

ABSTRACT

Taxanomic studies on eight species of Vigna Savi (Leguminosae —Papilionoideae) in eastern part of Nigeria were carried out using morphological, anatomical, histochemical, palynological, cytological and distributional lines of evidence. Morphological attributes of these taxa showed that V. graci/ils, V. reticu/ata, V. vexi/ata, and V. racemosa are creeping herbs while V trioba, V. unguicu/ata, V. ambacensis and V. subterranea are climbing herbs. The floral symmetry of V. grad//is, V. reticu/ata, V. vexi//ata, V. unguiculata, V. racemosa and V. subterranea are actinomorphic while V. trioba and V. ambacensis are zygomorphic. All the eight species of V,'na studied are amphistomatic with anomocytic type of stomata. The epidermal walls of V. subterranea, V. trioba, V. ret/cu/ata and V. vexilata have multiseriate cells while V. ambacensis, V. racemosa, V. grad//s and V. unguicu/ata have uniseriate cells. The cell wall architecture of the upper epidermal layer of V grad/is, V. reticulata and V. trioba are regular while V. unguicu/ata, V. vexi//ata, V. racemosa, V. subterranea and V. ambacensis are sinuous. The petiolar anatomy •of V grad/is and V. racemosa have prismatic crystals while others have crystal sand. In the nodal anatomy, there are prismatic crystals in V. unguicu/ata and crystal sand in others. The pollen grain is circular and psilate (smooth) in V. reticu/ata, circular and echinate in V. unguicu/ata and V. racemosa, elliptic and monocolpate in V ambacensis and V. vexi//ata, circular and polyporate in V. subterranea, circular and dicolpate in V. gra c/I/is and V. trioba. The distributional studies separated the species into wild and cultivated species hence the need to preserve and conserve the wild species based on their economic potentials. The overall results of these investigations are of taxanomic importance used for the establishment of the interspecific relationships among the Vigna species studied and discussed the taxonomic positions of the different taxa. This is in view of the apparent difficulties in the taxonomy of the Vigna species as a whole.