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• Taxonomy
• Physical Description
• Distribution
• Similar Species
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Taxonomy

Physical Description

Family Poaceae:

Annual or perennial herbs, or tall woody bamboos. Flowering stems (culms) jointed, internodes hollow or solid; branches arising singly from nodes and subtended by a leaf sheath and 2-keeled prophyll, often fascicled in bamboos. Leaves arranged alternately in 2 ranks, differentiated into sheath, blade, and an adaxial erect appendage at sheath/blade junction (ligule) ; leaf sheath surrounding and supporting culm-internode, split to base or infrequently tubular with partially or completely fused margins, modified with reduced blade in bamboos (culm sheaths) ; leaf blades divergent, usually long, narrow and flat, but varying from inrolled and filiform to ovate, veins parallel, sometimes with cross-connecting veinlets (especially in bamboos) ; ligule membranous or a line of hairs. Inflorescence terminal or axillary, an open, contracted, or spikelike panicle, or composed of lax to spikelike racemes arranged along an elongate central axis, or digitate, paired, or occasionally solitary; axillary inflorescences often many, subtended by spatheoles (specialized bladeless leaf sheaths) and gathered into a leafy compound panicle; spikelets often aggregated into complex clusters in bamboos. Spikelets composed of distichous bracts arranged along a slender axis (rachilla) ; typically 2 lowest bracts (glumes) empty, subtending 1 to many florets; glumes often poorly differentiated from accompanying bracts in bamboos. Florets composed of 2 opposing bracts enclosing a single small flower, outer bract (lemma) clasping the more delicate, usually 2-keeled inner bract (palea) ; base of floret often with thickened prolongation articulated with rachilla (callus) ; lemma often with apical or dorsal bristle (awn), glumes also sometimes awned. Flowers bisexual or unisexual; lodicules (small scales representing perianth) 2, rarely 3 or absent, 3 to many in bamboos, hyaline or fleshy; stamens 3 rarely 1, 2, 6, or more in some bamboos, hypogynous, filaments capillary, anthers versatile; ovary 1-celled, styles (1 or) 2(rarely 3), free or united at base, topped by feathery stigmas, exserted from sides or apex of floret. Fruit normally a dry indehiscent caryopsis with thin pericarp firmly adherent to seed, pericarp rarely free, fleshy in some bamboos; embryo small or large; hilum punctate to linear.

About 700 genera and 11,000 species: widely distributed in all regions of the world.^[1]

Genus Elymus:

Plants perennial, usually tufted, usually without, rarely with, rhizomes. Culms usually erect. Leaf sheath of cauline leaves split almost to base; auricles present or absent; leaf blade flat or rolled. Spike erect to nodding. Spikelets 1 or 2(4) per node, sessile, rarely very shortly pedicellate, appressed to rachis, clearly laterally compressed, usually all similar, with 210 or more florets; rachis tough. Glumes opposite or side-by-side, linear-lanceolate to lanceolate-ovate, firmly membranous to leathery, 19(11) -veined, not keeled, apex obtuse to shortly awned; veins ± raised. Lemma lanceolate-oblong, rounded abaxially, 5-veined, ± pubescent, apex obtuse or acute to awned, rarely toothed; veins connivent at apex; awn erect or reflexed. Palea shorter than or equaling lemma, apex retuse, subrounded, or acute. Caryopsis usually adherent to lemma and palea. x = 7.

About 170 species:temperate regions of both hemispheres, mainly in Asia; 88 species (62 endemic) in China.

The genus Roegneria should be referred to Elymus because of their many common characters, e.g., plants usually tufted; spikelets usually all similar, 1 per node; lemma lanceolate-oblong, rounded abaxially, 5-veined, veins connivent at apex.^[2]

Distribution

Similar Species

Members of the genus Elymus:

There are approximately 1,008 species, subspecies, varieties, forms, and cultivars in this genus. Here are just 100 of them: E. alaskanus alaskanus · E. alaskanus islandicus · E. alaskanus kronokensis · E. alaskanus sajanensis · E. alaskanus scandicus · E. alaskanus subalpinus · E. alaskanus villosus · E. arenarius sabulosus · E. asiaticus longearistatus · E. batalinii alaica · E. bungeanus pruiniferus · E. bungeanus scythicus · E. campestris maritimus · E. canadensis wiegandii · E. caninus biflorus · E. caninus donianus · E. ciliaris integris · E. confusus pilosifolius · E. dahuricus cylindricus · E. dahuricus micranthus · E. dahuricus pacificus · E. dahuricus villosulus · E. dentatus elatus · E. dentatus lachnophyllus · E. dentatus scabrus · E. donianus novae-angliae · E. donianus virescens · E. elongatus flaccidifolius · E. elongatus haifensis · E. elongatus salsus · E. elongatus turcicus · E. elymoides brevifolius · E. elymoides californicus · E. elymoides hordeoides · E. farctus bessarabicus · E. farctus boreali-atlanticus · E. franchetii pacificus · E. glaucus mackenzii · E. glaucus virescens · E. gmelinii tenuisetus · E. gmelinii ugamicus · E. hispidus graecus · E. hispidus podpyerae · E. hispidus pouzolzii · E. hispidus pulcherrimus · E. hyparcticus villosus · E. kronokensis dasyphyllus · E. kronokensis scandicus · E. lanceolatus albicans · E. lanceolatus yuonensis · E. lazicus attenuatiglumis · E. lazicus divaricatus · E. lazicus lomatolepis · E. longearistatus badachschanicus · E. longearistatus canaliculatus · E. longearistatus duthiei · E. longearistatus flexuosissimus · E. longearistatus litvinovii · E. macrourus neplianus · E. macrourus pilosivaginatus · E. mollis interior · E. multiflorus kingianus · E. mutabilis barbulata · E. mutabilis transbaicalensis · E. nodosus caespitosus · E. nodosus corsicus · E. nodosus dorudicus · E. nodosus gypsicolus · E. nodosus platyphyllus · E. nodosus sinuatus · E. panormitanus sirouanus · E. pauciflorus laevis · E. pauciflorus pseudorepens · E. pauciflorus subsecundus · E. pendulinus multiculmis · E. pendulinus pubicaulis · E. pungens fontqueri · E. pungens pycnanthus · E. reflexiaristatus strigosus · E. repens atlantis · E. repens calcareus · E. repens elongatiformis · E. sajanensis villosus · E. schrenkianus pamiricus · E. semicostatus alienus · E. semicostatus scabridulus · E. semicostatus striatus · E. semicostatus thomsonii · E. tauri pertenuis · E. thoroldianus laxiusculus · E. trachycaulus bakeri · E. trachycaulus donianus · E. trachycaulus kamczadalorum · E. trachycaulus scribneri · E. trachycaulus sierrus · E. trachycaulus stefanssonii · E. trachycaulus teslinensis · E. transhyrcanus lorestanicus · E. truncatus trichophorus · E. uralensis prokudinii

Bibliography

• Chen Shouliang, Jin Yuexing, Zhuang Tide, Fang Wenzhe, Sheng Guoying, Liu Liang, Wu Zhenlan, Lu Shenglian, Sun Bisin, Hu Zhihao, Wang Song, Sun Xiangzhong, Wang Huiqin, Yang Xilin, Wang Chaopin, Li Binggui & Wen Shaobin. 1990. Gramineae (Poaceae) (4). In: Chen Shouliang, ed., Fl. Reipubl. Popularis Sin. 10(1):1401
• Chen Shouliang, Zhuang Tide, Fang Wenzhe, Sheng Guoying, Jin Yuexing, Liu Liang, Sun Bisin, Hu Zhihao & Wang Song. 1997. Gramineae (Poaceae) (5). In: Chen Shouliang, ed., Fl. Reipubl. Popularis Sin. 10(2): 1301
• Liu Liang, Zhu Taiping, Chen Wenli, Wu Zhenlan & Lu Shenglian. Gramineae (Poaceae) (2). In: Liu Liang, ed., Fl. Reipubl. Popularis Sin. 9(2): 1405
• Lu Sheng-lian, Sun Yong-hua, Liu Shang-wu, Yang Yong-chang, Wu Zhen-lan, Kuo Pen-chao, Yang Hsi-ling, Wang Chao-pin & Tsui Nai-ran. 1987. Gramineae (3). In: Kuo Pen-chao, ed., Fl. Reipubl. Popularis Sin. 9(3): 1329
• Wang Zhengping, Ye Guanghan, Yang Yaling, Yu Zehua, Hu Chenhua, Geng Bojie, Feng Xuelin, Jia Liangzhi, Xia Nianhe, Li Dezhu, Zhang Weiping, Xue Jiru, Zhu Zhengde, Zhao Qiseng, Chen Shouliang, Sheng Guoying, Chen Shaoyun, Yao Changyu, Lu Jionglin, Sun Jiliang, Lin Wantao, Yi Tongpei, Zhao Huiru, Wen Taihui & Dai Qihui. 1996. Gramineae (Poaceae) (1).

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Notes

Contributors:

• Brands, S.J. (comp.) 1989-2006. Systema Naturae 2000. The Taxonomicon. Universal Taxonomic Services, Amsterdam, The Netherlands. Accessed October 4, 2006.
• Global Biodiversity Information Facility. Accessed September 18, 2006. http://www.gbif.org

Identifiers:

• Global Biodiversity Information Facility Taxonkey: 2440199
• Natural Heritage Network Species Identifier: PMPOA2H1J0
• Zipcode Zoo Species Identifier: 170075

Footnotes:

1. Shou-liang Chen, De-Zhu Li, Guanghua Zhu, Zhenlan Wu, Sheng-lian Lu, Liang Liu, Zheng-ping Wang, Bi-xing Sun, Zheng-de Zhu, Nianhe Xia, Liang-zhi Jia, Zhenhua Guo, Wenli Chen, Xiang Chen, Yang Guangyao, Sylvia M. Phillips, Chris Stapleton, Robert J. Soreng, Susan G. Aiken, Nikolai N. Tzvelev, Paul M. Peterson, Stephen A. Renvoize, Marina V. Olonova & Klaus Ammann "Poaceae". in Flora of China Vol. 22. Published by Science Press (Beijing) and Missouri Botanical Garden Press. Online at EFloras.org.
2. "Elymus". in Flora of China Vol. 22 Page 1, 386, 387, 400. Published by Science Press (Beijing) and Missouri Botanical Garden Press. Online at EFloras.org.