Poa royleana (Gramineae), a Little-Known Species from Western Himalaya

Abstract

Summary. Poa royleana Nees ex Steudel, treated as a synonym of Poa annua by earlier authors, was found to be different from P. annua after examination of the type specimen and is compared with the other species of Himalayan Poa having similar spikelet characters. Poa royleana was collected by J. F. Royle more than 150 years ago in Mussooree, western Himalaya and was described in Steudel's Synopsis Plantarum Glumacearum, named by Nees von Esenbeck. This species was treated as a synonym of P. annua L. by Stapf (1897), Bor (1952, 1960) and Cope (1982). No further reference to this species has been traced, although Bor (1954) mentioned that he examined the grasses from Royle's recently rediscovered herbarium which were sent on loan to Kew. This paper also contains useful additional information on the involvement of Nees von Esenbeck in the identification of the grasses in Royle's herbarium. Recently, we examined the type specimen of this species which is preserved in the Herbarium of the Liverpool Museum (LIV). The description of the type specimen of P. royleana is given here. The specimen is a perennial plant and is more than 80 cm tall, the spikelets of which have no trace of ciliate hairs on callus, keel and nerves of lemma and keels of palea. The specimen is thus quite different from P. annua. Moreover, the lemmas, especially those of the lowest florets, are usually 7-nerved. In this character it is distinct from other species of Himalayan Poa. However, the lemmas of upper florets in some spikelets are 5-nerved.