Puccinellia distans |
Poaceae subfam. pooideae |
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European alkali grass, puccinellie a fleurs distantes, spreading alkali grass, weeping alkaligrass |
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Habit | Plants perennial; cespitose, not mat-forming. | Plants annual or perennial; sometimes matlike, sometimes cespitose, sometimes stoloniferous, sometimes rhizomatous. | ||||||||||||||||||||||||||||||||||||
Culms | 5-60 cm, erect to decumbent. |
usually hollow, sometimes solid. |
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Leaves | distichous; sheaths usually open to the base, varying to closed for nearly their full length; auricles present or absent; abaxial ligules absent; adaxial ligules scarious or membranous, sometimes puberulent or scabridulous, usually not ciliate, cilia sometimes shorter than the base; pseudopetioles rarely present; blades usually linear, sometimes broadly so, venation parallel; cross sections non-Kranz, mesophyll nonradiate, adaxial palisade layer absent, fusoid and arm cells usually absent; midribs usually simple; adaxial bulliform cells present; stomates with parallel-sided subsidiary cells; epidermes usually lacking bicellular microhairs, sometimes with unicellular microhairs, papillae usually absent, when present, rarely more than 1 per cell. |
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Panicles | 2.5-20 cm, diffuse at maturity, lower branches horizontal to descending, spikelets usually confined to the distal 2/3, pedicels scabrous, lacking tumid epidermal cells. |
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Inflorescences | usually terminal, panicles, spikes, or racemes, usually ebracteate; disarticulation usually below the florets, sometimes below the glumes, at the rachis nodes, or at the inflorescence bases. |
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Spikelets | 2.5-7 mm, with 2-7 florets. |
usually bisexual, infrequently unisexual or mixed, usually laterally compressed or not compressed, occasionally dorsally compressed, with 1-30 sexual florets, distal floret(s) often reduced, infrequently spikelets with 1-2 reduced or staminate basal florets and a single terminal sexual floret. |
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Glumes | rounded over the back, veins obscure, apices acute to truncate; lower glumes 0.4-1.3 mm; upper glumes 0.9-1.8 mm; calluses with a few hairs; lemmas 1.5-2(2.2) mm, mostly herbaceous, glabrous or sparsely hairy on the lower 1/2, principally along the veins, backs rounded, 5-veined, veins obscure, not extending to the margins, apical margins hyaline and often yellowish, uniformly and densely scabrous, apices widely obtuse to truncate, entire; palea veins shortly ciliate proximally, glabrous, sometimes scabrous distally; anthers 0.4-0.8 mm. |
usually 2, upper or lower glumes sometimes absent, rarely both glumes absent; lemmas without uncinate hairs, awned or not, awns single, basal to apical; paleas usually well-developed, sometimes reduced or absent; lodicules 2(3), usually lanceolate and broadly membranous distally, rarely truncate and fleshy, usually not veined or obscurely veined, sometimes distinctly veined, sometimes ciliate; anthers (1, 2)3; ovaries glabrous or sometimes hairy distally, sometimes with an apical appendage; haustorial synergids absent; styles (1)2 (-4), bases close together, sometimes fused. |
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Caryopses | hila linear, elliptic, ovate, or punctate; endosperm usually hard, sometimes soft or liquid, with or without lipids, starch grains compound or simple; embryos less than 1/2 the length of the caryopses; epiblasts usually present; scutellar cleft usually absent; mesocotyl internode usually absent; embryonic leaf margins overlapping, x = 7, 10. |
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Ligules | 0.8-1.2 mm, obtuse to truncate, usually entire; blades 1-7 mm wide, flat to involute. |
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2n | = 14, 28, 42. |
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Puccinellia distans |
Poaceae subfam. pooideae |
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Distribution |
AK; AZ; CA; CO; CT; DE; IA; ID; IL; IN; KY; MA; MD; ME; MI; MN; MO; MT; NC; ND; NE; NJ; NM; NV; NY; OH; OR; PA; RI; SD; UT; VA; VT; WA; WI; WV; WY; AB; BC; MB; NB; NL; NS; ON; PE; QC; SK; YT; Greenland
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Discussion | Puccinellia distans is a Eurasian native, reportedly introduced in North America, where it is widespread, particularly as a weed in non-littoral environments, including the margins of salted roads. It is also found occasionally in coastal environments. A specimen in the Smithsonian Institution attributed to Puccinellia tenuiflora (Griseb.) Scribn. & Merr. by Scribner and Merrill (1910) is a robust example of P. distans; others of this taxon in North America remain to be investigated. Puccinellia hauptiana (Trin. ex V.I. Krecz.) Kitag. has been reduced to P. distans subsp. hauptiana (Trin. ex V.I. Krecz.) W.E. Hughes. This taxon may represent a tetraploid component of P. distans; several specimens identified as P. hauptiana in Eurasia have a tetraploid chromosome count. Specimens from Alaska, the Yukon, and Saskatchewan, identified as P. hauptiana on the basis of their relatively narrow leaves (1-2 mm wide) and small anthers (0.5-0.6 mm), appear to be native in these regions and require further study with regard to their relationship with P. distans. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
The subfamily Pooideae includes approximately 3300 species, making it the largest subfamily in the Poaceae. It reaches its greatest diversity in cool temperate and boreal regions, extending across the tropics only in high mountains. The circumscription and relationships of tribes within the Pooideae are unsettled (see, for example, Catalan et al. 1997, 2004; Soreng and Davis 1998). In this flora, some previously recognized tribes have been combined with the Poeae. Recognition of some of these as subtribes is well supported; among these is the Hainardieae Greuter (which, at the subtribal level, is called the Parapholiinae Caro). Members of other traditional tribal groupings, such as the Aveneae Dumort., appear to be widely dispersed within the Poeae sensu lato. Further work will probably support the division of the expanded Poeae into additional tribes; there is as yet no clear indication as to what the boundaries of such tribes should be. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 24, p. 473. | FNA vol. 24, p. 57. | ||||||||||||||||||||||||||||||||||||
Parent taxa | Poaceae > subfam. Pooideae > tribe Poeae > Puccinellia | Poaceae | ||||||||||||||||||||||||||||||||||||
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Synonyms | P. retroflexa, P. hauptiana | |||||||||||||||||||||||||||||||||||||
Name authority | (Jacq.) Pari | Benth. | ||||||||||||||||||||||||||||||||||||
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