SYSTEMATIC STUDY OF THE GENUS “Combretum” Loefl. IN NORTHERN NIGERIAN SAHELIAN SAVANNAH: A CASE STUDY OF KATSINA STATE
DOI:
https://doi.org/10.33003/fjs-2026-1006-4470Keywords:
Genus Combretum, Katsina state, Northern Nigerian, Systematic study, Sahelian savannahAbstract
A systematic investigation of the genus Combretum in the Northern Nigerian Sahelian savannah was conducted using Katsina State as a case study, with the aim of assessing phylogenetic relationships and revising the taxonomy of species present in the region. Field surveys resulted in the collection of four Combretum species, which were analyzed using morphometric and molecular approaches. Cluster analysis based on morphometric characters revealed that all species were distinct at a Euclidean distance of 6. The species were identified as Combretum ghasalense, C. molle, C. micranthum, and C. glutinosum. A high cophenetic correlation coefficient (r = 0.98) indicated strong similarity among the taxa. Ordination analysis supported the cluster results by separating the specimens into four distinct groups. Principal Component Analysis (PCA) showed that the first two components accounted for 73.3% and 25.4% of the total morphological variation, respectively. For phylogenetic inference, genomic DNA was extracted from all specimens, and the chloroplast rbcL gene region was amplified, sequenced, and analyzed using Bayesian inference on the CIPRES portal. The results demonstrated that Combretum is monophyletic with strong posterior probability support (PP = 1.0). Several clades were strongly supported, while others showed moderate support. The phylogenetic tree revealed that C. ghasalense and C. micranthum are sister species within the same clade, whereas C. molle and C. glutinosum formed a closely related clade, indicating shared evolutionary history.
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