Belongs within: Pooideae.
Deyeuxia is a genus of grasses found in temperate habitats. The reed bent-grass D. quadriseta bears dense, long, cylindrical panicles in which lemmas are less than two-thirds the length of the glumes. Lemmas are shorter in the species D. drummondii and D. inaequalis (Gardner 1952).
Characters (Cheeseman 1906): Annual or perennial grasses. Leaves flat or involute ; ligules membranous. Spikelets small, 1-flowered, arranged in effuse or contracted or spike-like panicles with capillary whorled branches; rhachilla disarticulating above the 2 outer glumes, produced beyond the flower into a silky bristle. Glumes 3; 2 outer equal or subequal, persistent, empty, keeled, acute, not awned, usually 1-nerved; third or flowering glume shorter than the empty glumes or equalling them, thin and hyaline or rigidly membranous or almost coriaceous, 5-nerved, entire or 2–4-dentate, callus at the base silky; awn generally present, straight or twisted, inserted above or below the middle of the glume. Palea more than half as long as the flowering glume or almost equalling it, thin, 2-nerved or 2-keeled. Stamens 3. Styles distinct, short; stigmas plumose. Grain oblong or obovoid, enclosed within the flowering glume and palea.
<==Deyeuxia [incl. Bromidium]B78
|--D. aequata [=Agrostis aequata]B78
|--D. aucklandicaW91
|--D. avenoides [=Agrostis avenoides]C06
| |--D. a. var. avenoidesC06
| `--D. a. var. brachyantha Hack. in Cheeseman 1906C06
|--D. billardieri [=Agrostis billardieri]C06
| |--D. b. var. billardieriC06
| `--D. b. var. tenuis Petrie in Cheeseman 1906C06
|--D. breviglumisB78
|--D. densaB78
|--D. drummondii (Steud.) Vicker 1940G52 [=Pentapogon drummondiiB78]
|--D. filiformisAn27
|--D. frigida [=Agrostis frigida]B78
|--D. gunniana [=Echinopogon gunnianus]B78
|--D. holciformisO88
|--D. inaequalis Vickery 1940G52
|--‘Agrostis’ leptostachyaC06
|--‘Calamagrostis’ lilloi Hackel in Stuckert 1906S06
|--‘Calamagrostis’ malamalensis Hackel in Stuckert 1906S06
|--D. minor [=Agrostis quadriseta var. minor]B78
|--D. montana [=Agrostis montana]B78
|--D. nepalensisO88
|--D. nivalis [=Agrostis nivalis Muell. 1855]B78
|--D. nivicolaO88
|--D. petrieiC06 [=Calamagrostis petriei Hack. 1903C06, D. youngii var. petrieiAl27]
|--D. pulchellaO88
|--D. quadriseta (Labill.) Benth. 1878G52 (see below for synonymy)
| |--D. q. var. quadrisetaG52
| `--D. q. var. cylindrica [=Agrostis cylindrica]G52
|--D. scabrescensO88
|--D. setifolia [=Agrostis setifolia]C06
|--‘Calamagrostis’ spiciformis Hackel in Stuckert 1906S06
`--D. youngii [=Agrostis youngii]C06
Deyeuxia quadriseta (Labill.) Benth. 1878G52 [=Agrostis quadrisetaB78, Avena quadrisetaB78, Bromidium quadrisetumB78, Calamagrostis quadrisetaG52; incl. Agrostis diaphoraB78, Ag. lobataB78, Bromidium lobatumB78]
*Type species of generic name indicated
References
[Al27] Allan, H. H. 1927. The vegetation of Mount Peel, Canterbury, New Zealand. Part 2.—The grassland and other herbaceous communities. Transactions and Proceedings of the New Zealand Institute 57: 73–89.
[An27] Andersen, J. C. 1927. Popular names of New Zealand plants. Part 2. Transactions and Proceedings of the New Zealand Institute 57: 905–977.
[B78] Bentham, G. 1878. Flora Australiensis: A description of the plants of the Australian Territory vol. 7. Roxburghiaceae to Filices. L. Reeve & Co.: London.
[C06] Cheeseman, T. F. 1906. Manual of the New Zealand Flora. John Mackay, Government Printer: Wellington.
[G52] Gardner, C. A. 1952. Flora of Western Australia vol. 1 pt 1. Gramineae. William H. Wyatt: Perth.
[O88] Ohba, H. 1988. The alpine flora of the Nepal Himalayas: an introductory note. In: Ohba, H., & S. B. Malla (eds) The Himalayan Plants vol. 1. The University Museum, University of Tokyo, Bulletin 31: 19–46.
[S06] Stuckert, T. 1906. Segunda contribución al conocimiento de las gramináceas Argentinas. Anales del Museo Nacional de Buenos Aires, serie 3, 6: 409–555.
[W91] Williams, P. A. 1991. Subalpine and alpine vegetation of granite ranges in western Nelson, New Zealand. New Zealand Journal of Botany 29: 317–330.