Abstract

     The present research includeda comparative epidermal and anatomical Study of the leaflets of six species belonging to the genus Senna.Mill. and growing  in Toor  Al- Baha District, Lahj  Gov., Yemen  viz: 1-S. alexandrina 2-S. holosericea 3-S.italica 4- S. obtusifolia 5-S. occidental 6- S. sophera The study involved the epidermal characters such as the ordinary epidermal cells, stomata and epidermal tricomes ( hairs). The results revealed the occurance  some features which were helpful for the differentiation between  the studied  species such as epidermal cells shape, anticlinal cell walls patterns, stomatal types ,stomatal index and epidermal tricomes, and through which an artificial key was made to identify the studied species.