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Diarrhena P.Beauv.

Kingdom: Plantae Rank: Genus Parent: Poaceae Status: Valid

Common Names:

  • BEAKGRAIN - English, United States of America

Morphological Description

Diagnosis: Rhizomatous perennials; culms arching; leaves basal and on lower stem; ligule a membrane; leaf blades flat; inflorescence a long-exserted, arching, narrow panicle with ascending branches; spikelets with 25(7) florets, the terminal floret reduced and sterile, the florets often spreading at maturity; disarticulation above glumes and between florets; glumes 2, unequal, awnless; lemmas rounded on back, 3-veined, awnless, with a sharp cusp 12 mm long at apex; caryopsis (= fruit or grain) with a beak.


Notes: A C₃ genus of ca. 6 perennial species (Brandenburg ined.) of woodlands of e Asia and e North America, only 2 of the species are North American; this disjunct distribution pattern is discussed under the genus Brachyelytrum (Poaceae). Some authors, however, have treated the Asian taxa in a separate genus, Neomolinia Honda (e.g., Tsvelev 1989, who recognized Neomolinia as having 5 species). Subfamilial classification of Diarrhena is problematic, with some authorities putting it in the Pooideae and others in the Bambusoideae (Brandenburg et al. 1991a); recent evidence suggests the appropriate placement is in the Pooideae (Grass Phylogeny Working Group 2001). The following key is from Brandenburg et al. (1991a). (Greek: di, two or twice, and arrhen, male, from the two stamens) (subfamily Pooideae, tribe Diarrheneae)