The relationship among six species of the genus Senna is described using eight quantitative characters based on both fresh and herbarium specimens. The Principal Component Analysis results show that the number of leaflets, leaflet length, and leaflet breadth are the only three features that have a substantial impact on the taxonomic delimitation. Based on farthest neighbor, mean character difference, and constrained clustering strategy, cluster analysis and dendrogram reveal that there is a greater degree of dissimilarity between Senna italica and S. sophera, while there is a lower degree between S. auriculata and S. italica. These results suggest that the two species are closely related. Ultimately, this research has illustrated the value of numerical analysis in taxonomic work by combining several morphological characteristics to produce a large enough demarcation that has better implications for these species taxonomy