ABSTRACT

Studies on the taxonomy of eight species of Ind(gofera L. (Leguminosae — Papilionoideae) in Eastern Nigeria were undertaken. These studies were based on such lines of evidence as morphology, anatomy, histochemistry, palynology, epidermal morphology, distribution and cytology to evaluate their reliability as aids in systematic identification of plants. Morphological attributes of these taxa revealed a clear relationship between I. prieureana and I. stenophy/la. The anatomical result showed that variation in the epidermal wall shape, cell type and number of lignified layer in these taxa are diagnostic. Futhermore, the difference in size of the cells of the cortex and a lacunar-collenchyma separating the epidermis from the cortex in these taxa is of taxanomic importance. All the eight species of Indigofera investigated are amphistomatic. Two different stomatal types (anomocytic & anisocytic) were present in these taxa. I. pu/chra and I. stenophylla are unique in possessing all the two types though the anomocytic type of stomata is predominant. Three types of pollen shape: circular, elliptic and oval are present in these taxa and variations in shape; wall sculpture and aperture are of taxonomic importance. Tanniferous bags were uniformly arranged on the palisade mesophyll of I. senega/ensis while I. stenophy/la has starch grains. Crystals of various shapes found in different organs of these taxa are diagnostic and could be used in establishing interspecific relationship among the Indigo fera species investigated. Geographical distribution of these taxa offers better insight into the natural pattern of these taxa in the country particularly the Eastern region. The general implications of the results of our investigations in the systematic recognition of these taxa have been discussed. This is in relationship to the confused nature of the taxonomy of the Indigofera species despite their immense value in industry, medicine/pharmaceutical and agriculture.