Quantitative Leaf Morphological Analysis of Different Senna Species in Zaria Metropolis, Kaduna State, Nigeria

The close similarity in the foliar characteristics of Senna species makes their identification tedious and puzzling. A study was conducted to identify variations in the leaf morphological characteristics of different Senna species in Zaria, Kaduna State, Nigeria with the aim of providing firsthand information that will be useful for their proper identification. Six quantitative leaf characters of seven different Senna species in Zaria were measured using standard methods of measurement. Analysis of variance and principal component analysis (PCA) were used to analyze the data obtained. The results revealed significant differences (P ≤ 0.05) in the size and number of leaves and leaflets of the seven Senna species under study. S. siamea had the highest number of leaves (9 leaves), while S. hirsuta had the least number of leaves (4 leaves). However, S. singueana had the largest leaf area at (68.96 cm²), while S. siamea had the smallest leaves among the studied species. Furthermore, S. alata had the highest number of leaflets. The study found that the six characters used contributed significantly to differentiating each species, despite their morphological similarities, which is the basis for their grouping under the same genus. It was also found that Senna alata and Senna siamea are more closely related. Similarly, Senna sieberiana, Senna singueana, and Senna obtusifolia showed a close resemblance, while Senna hirsuta is distantly related to the others.