Page 11 Research Article Journal of Research and Review in Science, 11-16 Volume 6, December 2019 LASU Journal of Research and Review in Science Diagnostic Petiole Anatomical Characters and Their Systematic Importance in 18 Species of the Genus Tephrosia Pers. (Fabaceae) found in Nigeria. Oluwa, O.K., 1,* Olowokudejo, J.D. 2 and Ogundipe, T.O. 2 1 Department of Botany, Lagos State University, Ojo, Lagos, Nigeria. 2 Department of Botany, University of Lagos, Akoka, Lagos, Nigeria. Correspondence Oluwa, O.K, Department of Botany, Faculty of Science, Lagos State University, Ojo, Nigeria. Email: oluwateso@yahoo.com +234 (0) 802-315-0058 Abstract: A comprehensive systematic anatomical investigation of diagnostic petiole characters of eighteen (18) species of Tephrosia found in Nigeria was carried out. Tephrosia Pers. belongs to the family Fabaceae, tribe Milletteae. It habits the fringes of the forests, abandoned wastelands. The eighteen (18) species include T. bracteolata, T. candida, T. densiflora, T. elegans, T. flexuosa, T. hildebrandtii and T. hirsuta. Others are T. interupta, T. leptostachya, T. linearis, T. lupinifolia, T. mossiensis, T. nana, T. noctiflora, T. paniculata, T. pedicellata, T. purpurea and T. vogelii. The study is aimed at using petiole characters to delimit, and establish any infrageneric groups based on the variations and affinities within the petiolar characters. A total of nine (9) diagnostic polymorphic characters were observed, photographed, assessed, scored and coded. These include Petiole Symmetry (PSY), Petiole Outline (POL), Petiole Vascular System (PVS), Petiole Perivascular Tissue (PPT), and Petiole Trichome Cell type (PTC) and Petiole Trichome Base (PTB). These characters are either multistate or binary. Principal Component Analysis and Cluster Analysis were carried out. A total of six (6) tables and three (3) figures were generated from the statistical treatment of the data matrix constructed. The Principal Component Analysis using Extraction method revealed four (4) principal components. High Level of dissimilarity among the species suggests distinct species. Highest number of similar species was three (3) which are T. leptostachya, T. purpurea and T. mossiensis while in morphology are much alike. The cluster analysis separated the group into twelve (12) hierarchies. Keywords: Tephrosia, Petiole, Anatomy, Systematics, Identification. All co-authors agreed to have their names listed as authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. © 2018 The Authors. Journal of Research and Reviews in Science – JRRS, A Publication of Lagos State University JRRS https:sciencejournal.lasucomputerscience.com DOI: 10.36108/jrrslasu/9102/60(0120)