Abstract:This paper is the first part of the study on the system and evolution ofgenus Themeda Forsskal. The nomenclature of Themeda Forsskal, Anthistiria Linn. f. andrelatives were reviewed. The legitimate name Themeda published by Peter Forsskal andseveral synonyrns were listed. Genera Themeda and Anthistiria being exadrined and correctedwere transferred into 10 genera, viz. Themeda Forssk. (70 binom. & 33 spp.), ExothecaAnderss. (1 binom. & 1 sp.), HyParrhenia Anderss, ex Fourn. (13 binom. & 7 spp.),ISeilema Anderss. (7 binom & 3 spp), Hyperthelia W. D. Clayton(1 binom. & 1 sp),Germainia Ba1ans. & Poitr. (2 binom. & 1 sp.), Pseudanthistiria (Hack.) Hook. f (1 binom.& 1 sp.), Tristachya Nees (1 binom. & 1 sp.), CymbOPogon Spreng (1 binom. & 1 sp.),Elymandra Stapf (1 binom. & 1 sp.). Four dubious specific names are presented. Historicalstudy on the systematics of Themeda and allied studies were briefly reviewed. The problemsof evolutionary trend and systernatic treatment have been proposed.