Taxonomical implications of foliar epidermal anatomy of Impatiens L. species (Balsaminaceae) in the Nilgiris, Southern Western Ghats, India

The foliar epidermal anatomy of 22 Impatiens species from the family Balsaminaceae was studied. The study intended to determine whether the micromorphological characteristics of the genus Impatiens were taxonomically significant and would aid in the precise identification of the species. The qualitative and quantitative traits as well as diagnostic characteristics were identified using a Light microscope. Variations were observed in both adaxial and abaxial leaf micromorphological characters like the shape of the epidermal and guard cells, anticlinal wall pattern, lobes per cell, stomatal pore, distribution of stomata, type of stomata and the presence and nature of trichomes. Anomocyic stomata exclusively occurred in all the studied Impatiens species. Stomata were present on both the surface of I. scabriscula B. Heyne ex Walland I. balsamina L., while in rest of the studied species stomata restricted on abaxial surface. An elliptical pore is the dominant type of stomatal pore among the investigated impatiens taxa. Uniseriate multicellular trichomes were observed (I. tenella B.Heyne ex Hook., I. fruticosa Lesch ex DC, I. gardeneriana Wight, I. minor (DC.) Bennet, I. rufescens Benth ex Wight & Arn). For accurate species delineation and identification in the genus Impatiens, taxonomic keys have been developed based on foliar micromorphology.