RESUMO
Calamagrostisnagarum, previously considered to be a poorly known species, has been reassessed taxonomically. It is a member of C.lahulensis-C.scabrescens complex and may be segregated by morphological characters such as the presence of pilose hairs on adaxial surface of leaf blades, spreading panicle branches, filiform awn and nerve prolongation of lemma. Besides, the micromorphology of adaxial surface of leaf blades, dorsal surface of glume and lemma differentiates Calamagrostisnagarum from its allies, C.lahulensis and C.scabrescens. It is known from Nagaland and Uttarakhand, India, and Bhutan. In this study, we have provided an emended description of the species, a discussion of its habitat and distribution, and taxonomic notes along with field photographs and photo plates for its correct identification. In addition, we also lectotypify the names C.lahulensis and C.scabrescens.