Flora of New Zealand Series

Type species: D. montana (Gaudich.) P.Beauv.  nom. illeg.

Tufted perennials, sometimes rhizomatous; branching extravaginal. Leaf-sheath rounded. Ligule membranous. Leaf-blade flat, involute, convolute or conduplicate. Culm erect, or decumbent at base, persistent at maturity; nodes glabrous. Inflorescence paniculate, contracted and ± spicate, often lobed below, or sometimes more lax, persistent. Spikelets 1-flowered, rarely 2-flowered, laterally compressed; disarticulation above glumes; rachilla usually prolonged and tipped by a tuft of silky hairs or rarely by a floret, sometimes rachilla prolongation glabrous and very short. Glumes ± equal and equalling the spikelet, lanceolate, acute or acuminate, membranous to submembranous, 1-(3)-nerved, keel scabrid. Lemma usually < glumes and firmer, submembranous to subcoriaceous, lanceolate, usually minutely denticulate, rounded, ± scabrid, ± obscurely 5-nerved, lateral nerves occasionally excurrent; awn dorsal, scabrid, geniculate or straight, inserted from near base of lemma to slightly above midpoint, to subterminal, rarely 0. Palea ≈ lemma, hyaline, 2-keeled. Lodicules 2, lanceolate or linear, acute to obtuse, membranous, glabrous. Callus short, blunt, with minute hairs, or the hairs to ⅔ or rarely ≈ lemma, rarely glabrous. Stamens 3; anthers rarely penicillate. Ovary glabrous; styles distinct, free to base, short; stigmas 2, plumose. Caryopsis compressed, fusiform to oblong or obovoid; embryo small; endosperm doughy or dry. Chasmogamous or cleistogamous.

c. 110 spp., Australasia, Malaysia, New Guinea, South America. Endemic spp. 4, indigenous sp. 1, shared with Australia.

New Zealand spp. were revised by Edgar, E. N.Z. J. Bot. 33: 1-33 (1995); a new endemic sp. was added by Edgar, E. and Connor, H. E. N.Z. J. Bot. 37: 63-70 (1999).

Deyeuxia is often included in Calamagrostis Adans., e.g., by Clayton and Renvoize (1986 op. cit.). However, Watson, L. and Dallwitz, M. J. Grass Genera of the World (1992) indicate that Deyeuxia is distinct from Calamagrostis in having callus hairs < lemma, or 0, and in the lemma being at least ¾ length of the glumes and firmer than them. In Calamagrostis callus hairs are = or » lemma, and the lemma is c. ½ - ¾ length of the glumes, usually hyaline, and less firm, or of similar texture to the glumes. Watson and Dallwitz also report significant differences between the two genera in leaf anatomy.