Micromorphological Diversity and Taxonomic Significance of the Leaf Epidermis in Cymbopogon Spreng. (Poaceae)

Abstract

              The genus Cymbopogon (Poaceae: Andropogoneae) comprises a medicinally and ethnobotanically important group of grasses with a wide global distribution, predominantly across tropical and subtropical regions. The present study conducts a comparative micromorphological analysis of the leaf epidermis in five species, C. citratus, C. martini, C. nardus, C. polyneuros, and C. iwarancusa, to evaluate their taxonomic significance. Detailed examination of foliar traits, including stomatal size, density, index, and shape, as well as epidermal cell number, subsidiary cells, silica bodies, trichomes, papillae, and prickles, was performed on both adaxial and abaxial surfaces. Marked interspecific variations were recorded in stomatal dimensions, density, and distribution patterns. C. polyneuros exhibited the largest stomata (82.43 ± 1.79 µm × 51.44 ± 1.33 µm) with a stomatal index of 28.57, whereas C. iwarancusa showed the smallest stomata (16.78 ± 0.37 µm × 13.39 ± 0.30 µm) and a stomatal index of 35.08. Distinct variations in silica body morphology, trichome types, and papilla distribution further differentiated the species. The observed micromorphological attributes serve as reliable diagnostic characters of high taxonomic value and also indicate adaptive responses to diverse ecological conditions.