Taxonomic account of the genus cyperus L.(cyperaceae) of Nepal

Abstract

Taxonomy enhances the understanding and adds vital information to understand the status of the taxa in the form of protologue which in turn will be used in flora writing. The genus Cyperus which belongs to tribe Cypereae, subfamily Cyperoideae and family Cyperaceae is the largest genus in the family after Carex. In this study a taxonomic treatment of the 36 species of Cyperus occurring in Nepal is presented. The treatment is based on herbarium study and field work. Description of all the taxa are given, as well as discussions of morphology and taxonomy of genus. This study includes a dichotomous key for the identification of the species, as well as illustrations, descriptions, taxonomic comments and geographical distribution. The Distance-based Neighbor-Joining (NJ) analyses were conducted using PAUP* 4.0a169 (Swofford, 2002) for the construction of Dendrogram. The mean characters difference was used for distance measurement, branch length represents the distance between nodes and internode and close relationship between species. Based on herbarium record, species of Cyperus are distributed from East to Central to West of Nepal. Vertical distribution of genus ranges from subtropical to tropical zone (80-2700m). Phenological period start from April and ends to January and shows peak at the month from June to October. Present study focuses on the morphological characters (inflorescence, rachilla internode length, spike and spikelets arrangement, shape, size, glumes colour, shape, size, tip, venation, keel, margin, stamen, pistil, and nutlets shape, size, texture) which are of much taxonomically significant for the identification and delimitation of taxa within the genus.