Echinochloa muricata |
Echinochloa |
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American barnyard-grass, awn barnyard grass, rough barnyard grass |
barnyard-grass, cockspur grass |
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Habit | Plants annual. | Plants annual or perennial; with or without rhizomes. | ||||||||||||||||||||||||||||||||||||||||||||||||||||
Culms | 80-160 cm, erect or spreading, sometimes rooting at the lowest nodes, often developing short axillary flowering shoots at most upper nodes when mature; lower nodes glabrous or puberulent; upper nodes glabrous. |
10-460 cm, prostrate, decumbent or erect, distal portions sometimes floating, sometimes rooting at the lower nodes; nodes usually glabrous; internodes hollow or solid. |
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Sheaths | glabrous; ligules absent; blades 1-27 cm long, 0.8-30 mm wide. |
open, compressed; auricles absent; ligules usually absent but, if present, of hairs; blades linear to linear-lanceolate, usually more than 10 times longer than wide, flat, with a prominent midrib. |
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Panicles | of primary culms 7-35 cm, rachises and branches glabrous or hispid, hairs to 3 mm, papillose-based; primary branches 2-8 cm, usually spreading and rather distant, often with secondary branches. |
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Inflorescences | terminal, panicles of simple or compound spikelike branches attached to elongate rachises, axes not terminating in a bristle, spikelets subsessile, densely packed on the angular branches; disarticulation below the glumes (cultivated taxa not or tardily disarticulating). |
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Spikelets | 2.5-5 mm, disarticulating at maturity, usually purple or streaked with purple, usually hispid, hairs papillose-based. |
plano-convex, with 2(3) florets; lower florets sterile or staminate; upper florets bisexual, dorsally compressed. |
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Glumes | membranous; lower glumes usually 1/4 - 2/5 as long as the spikelets (varying to more than 1/2 as long), unawned to minutely awn-tipped; upper glumes unawned or shortly awned; lower lemmas similar to the upper glumes in length and texture, unawned or awned, awns to 60 mm; lower paleas vestigial to well-developed; upper lemmas coriaceous, dorsally rounded, mostly smooth, apices short or elongate, firm or membranous, unawned; upper paleas free from the lemmas at the apices; lodicules absent or minute; anthers 3. |
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Upper glumes | about as long as the spikelets; lower florets sterile; lower lemmas unawned or awned, awns to 16 mm; lower paleas well-developed; upper lemmas broadly obovoid or orbicular, narrowing to an acute or acuminate coriaceous portion that extends into the membranous tip, boundary between the coriaceous and membranous portions not marked by minute hairs; anthers 0.4-1.1 mm. |
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Caryopses | 1.2-2.5 mm, broadly obovoid or spheroid, yellowish; embryos 1.4-2 mm, 80-91% as long as the caryopses. |
ellipsoid, broadly ovoid or spheroid; embryos usually 0.7-0.9 times as long as the caryopses. |
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x | = 9. |
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2n | = 36. |
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Echinochloa muricata |
Echinochloa |
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Distribution |
AL; AR; AZ; CA; CO; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY; MB; NB; NS; ON; QC; SK; Virgin Islands
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AL; AR; AZ; CA; CO; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY; HI; PR; AB; BC; LB; MB; NB; NS; ON; PE; QC; SK; Virgin Islands |
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Discussion | Echinochloa muricata is native to North America, growing from southern Canada to northern Mexico in moist, often disturbed sites (but not rice fields). It resembles E. crus-galli in gross morphology and ecology, but differs consistently by the characters used in the key. The two varieties tend to be distinct, but there is some overlap in both morphology and geography. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Echinochloa is a tropical to warm-temperate genus of 40-50 species that are usually associated with wet or damp places. Many of the species are difficult to distinguish because they tend to intergrade. Some of the characters traditionally used for distinguishing taxa, e.g., awn length, are affected by the amount of moisture available; others reflect selection by cultivation, e.g., non-disarticulation in grain taxa, mimicry of rice as weeds of rice fields. There are 13 species in the Flora region: five native and one possibly native, four established, two grown as commercial crops, and one in research. In North America, the most abundant species appears to be the introduced, weedy Echinochloa crus-galli, which closely resembles the native E. muricata. The confusion between the two species has caused them to be treated as the same species. This confusion is probably reflected in the mapping of both E. crus-galli and E. muricata. Echinochloa frumentacea and E. esculenta are grown for grain in India and in China and Japan, respectively, but not in North America. Echinochloa oryzoides and E. oryzicola are weeds whose success and distribution reflects their adaptation to the periodic inundations of commercial rice fields. Cytogenetic data suggest that Echinochloa frumentacea and E. esculenta are domesticated derivatives of E. crus-galli and E. colona, respectively (Yabuno 1962) and that E. oryzoides is very closely related to E. crus-galli (Yabuno 1984). Yabuno (1966) suggested that E. crus-galli is an allohexaploid produced by natural hybridization between the tetraploid E. oryzicola with a not-yet-discovered diploid species of Echinochloa and subsequent chromosome doubling. Studies using seed protein electrophoresis and isozyme analyses (Kim et al. 1989; Gonzalez-Andres et al. 1996; Asins et al. 1999), and molecular studies involving RAPD markers and DNA sequences (Hilu 1994; Roy et al. 2000) or PCR-RFLP techniques (Yasuda et al. 2001), will help in clarifying the phylogenetic problems in Echinochloa, providing that proper attention is paid to the morphological characterization of the plant materials used and that voucher specimens are preserved. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 25, p. 396. | FNA vol. 25, p. 390. | ||||||||||||||||||||||||||||||||||||||||||||||||||||
Parent taxa | Poaceae > subfam. Panicoideae > tribe Paniceae > Echinochloa | Poaceae > subfam. Panicoideae > tribe Paniceae | ||||||||||||||||||||||||||||||||||||||||||||||||||||
Sibling taxa | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Name authority | (P. Beauv.) Fernald | P. Beauv. | ||||||||||||||||||||||||||||||||||||||||||||||||||||
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