Kashmir Himalayas harbour tremendous floristic diversity marked by a high degree of compositional heterogeneity and endemism especially among grasses (Poaceae). The present paper adds alien species Catapodium rigidum (L.) C. E. Hubbard to grass floristics of the region. With an origin in Eurasia and natural distribution in circum-Mediterranean region, the species is an alien with sporadic occurrence in the area of study. It is diagnosed by the presence of 3–10 floreted spikelets and 1–3 mm long obtuse ligule. In the present work, taxonomic description of the species in the latest formats of grass description has been supplemented with illustrations of diagnostic parts, spikelet diagram and spikelet formula. The structure of the caryopsis and the unit of dispersal (diaspore) has also been described. A comparison of diagnostic parts of all the four species of the genus has been utilized to prepare a key to identification of all the four species of the genus.
The authors are grateful to Professor Incharge, Emerging Life Sciences Laboratory, Guru Nanak Dev University, Amritsar, Punjab (India) for Scanning Electron Microscopy (SEM). We are also thankful to Nusrat Jan for helping in map designing. The first author is thankful to the University Grants Commission, New Delhi for financial assistance under a major UGC project on phytolith studies on the grasses of the North West Himalayan region.