Aristida longespica

(Slim-Spike Three-Awn Grass, Slimspike Threeawn)

Conservation Status

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Population Analysis

For the 283,255 species in the Class Liliopsida (Monocotyledons), we average 3.99 observations each in our database; for the Slim-Spike Three-Awn Grass, we have 437 observations. Compared to other species in this Class, this species is extremely common.
A two-sample t-test can be used to determine whether the trend in observations of the Slim-Spike Three-Awn Grass is the same as the trend in observations of Liliopsida. Is this species just as common, as a proportion of all observations, as it once was? The answer is no, changes in observation rate of this species significantly differ from changes in observation rate of its Class. (t=2.644, p<0.005)
How do observation rates of the Slim-Spike Three-Awn Grass differ from those of Liliopsida? To answer this, we examined the percentage of observerations for Liliopsida that were observations of the Slim-Spike Three-Awn Grass each year. We then correlated this percentage with observation year. If observations of the Slim-Spike Three-Awn Grass are becoming more common relative to other species of Liliopsida, the correlation should be positive, but if it is becoming less common, the correlation should be negative. In fact, the correlation is negative (r=-.41), with a negative slope (m = -.001), suggesting that the Slim-Spike Three-Awn Grass may be in decline relative to other species of Liliopsida. This correlation is statistically significant. (F = 93.28, p<.05)
The scatter chart to the right shows the percentage of all observations for Liliopsida each year that were observations of the Slim-Spike Three-Awn Grass.

Taxonomy

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Domain: Eukaryota Whittaker & Margulis,1978 - eukaryotes
- Kingdom: Plantae Haeckel, 1866 - Plants
  - Subkingdom: Viridaeplantae Cavalier-Smith, 1981 - Green Plants
    - Phylum: Magnoliophyta Cronquist, Takhtajan & W. Zimmermann, 1966 - Flowering Plants
      - Subphylum: Spermatophytina (auct.) Cavalier-Smith, 1998 - Seed Plants
        Infraphylum: Angiospermae auct.
        Class: Liliopsida Scopoli, 1760 - Monocotyledons
        Subclass: Commelinidae Takhtajan, 1967
        Superorder: Poanae (Small, 1903) Takhtajan, 1997 ex Reveal & Doweld, 1999
        Order: Poales Small, 1903
        Family: Poaceae (poh-AY-see-ay) (R. Brown) Barnhart, 1895 - Grass Family
        Subfamily: Aristidoideae
        Tribe: Aristideae
        Genus: Aristida (ar-RISS-ti-duh) Linnaeus, Sp. Pl. 1: 82. 1753. - Threeawn
        Specific epithet: longespica Poir.
        Botanical name: Aristida longespica Poir.

Notes:

Place of publication: Encycl. Suppl. 1:452. 1810

Name verified on 25-Feb-2004 by ARS Systematic Botanists.

Physical Description

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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 Aristida:

Perennials, less often annuals or suffruticose. Culms tufted. Leaf blades usually basal, rolled or rarely flat. Inflorescence a narrow or open panicle. Spikelets with 1 floret; glumes scarious, narrow, unequal with the upper usually longer, 1(-3) -veined; floret callus bearded, obtuse to pungent or 2-toothed; lemma narrowly cylindrical or laterally compressed, convolute, glabrous or sparsely hairy; awn 3-branched, branches arising directly from lemma apex or seated on a straight or twisted column, persistent or disarticulating either at base or apex of column (always persistent in China), scabrid. Stamens 3.

About 300 species: widely distributed in tropical and warm-temperate regions of the world; ten species (six endemic) in China.

This genus is found on poor, dry soils in areas of low rainfall, but does not usually penetrate into true desert.^[2]

Distribution

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Range and Population

Native: Alabama, Arkansas, Connecticut, Delaware, Florida, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maryland, Massachusetts, Michigan, Mississippi, Missouri, Nebraska, New Hampshire, New Jersey, New York, North Carolina, Ohio, Oklahoma, Pennsylvania, South Carolina, Tennessee, Texas, Virginia, West Virginia, Wisconsin.

Similar Species

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Members of the genus Aristida:

Bibliography

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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
FNA Editorial Committee. 1993–. Flora of North America. (F NAmer)
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

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Contributors:

Global Biodiversity Information Facility. Accessed December 01, 2007. http://www.gbif.org Mediated distribution data from 26 providers.
USDA, ARS, National Genetic Resources Program. Germplasm Resources Information Network - (GRIN) [Online Database]. National Germplasm Resources Laboratory, Beltsville, Maryland. URL (May 04, 2008)

Data Sources:

Accessed through GBIF Data Portal December 01, 2007:

Missouri Botanical Garden, Missouri Botanical Garden
USDA PLANTS, USDA PLANTS Database
Utah State University, USU-UTC Specimen Database

Identifiers:

Global Biodiversity Information Facility Taxonkey: 15745442
Globally Unique Identifier: urn:lsid:ipni.org:names:389559-1
Natural Heritage Network Species Identifier: PMPOA0K0M0
Zipcode Zoo Species Identifier: 167021

Footnotes:

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.
Sheng-lian Lu, Shou-liang Chen & Sylvia M. Phillips "Aristida". in Flora of China Vol. 22 Page 453. Published by Science Press (Beijing) and Missouri Botanical Garden Press. Online at EFloras.org.

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Last Revised: May 05, 2008