Echinochloa colona |
Echinochloa oplismenoides |
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awnless barnyard grass, jungle rice, jungle ricegrass, or jungle-rice, small barnyard grass, watergrass |
Chihuahuan barnyard grass, Chihuahuan cockspur |
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Habit | Plants annual; erect or decumbent, cespitose or spreading, rooting from the lower cauline nodes. | Plants annual. |
Culms | 10-70 cm; lower nodes glabrous or hispid, hairs appressed; upper nodes glabrous. |
to 100 cm, erect, succulent, glabrous, branching from the lower nodes. |
Sheaths | glabrous; ligules absent, ligule region frequently brown-purple; blades 8-22 cm long, 3-6(10) mm wide, mostly glabrous, sometimes hispid, hairs papillose-based on or near the margins. |
glabrous or hispid with papillose-based hairs; ligules absent or the ligule region pubescent; blades 10-35 cm long, 5-10 mm wide. |
Panicles | 2-12 cm, erect, rachises glabrous or sparsely hispid; primary branches 5-10, 0.7-2(4) cm, erect to ascending, spikelike, somewhat distant, without secondary branches, axes glabrous or sparsely hispid, hairs 1.5-2.5 mm, papillose-based. |
15-30 cm, narrow; primary branches appressed to ascending, with papillose-based hairs at the base of the spikelets. |
Spikelets | 2-3 mm, disarticulating at maturity, pubescent to hispid, hairs usually not papillose-based, tips acute to cuspidate. |
4-5 mm, disarticulating at maturity. |
Glumes | with hairs over the veins, glabrous, scabrous, or hispid between the veins; upper glumes about equal to the spikelets, muticous or awned, awns to 1 mm; lower florets sterile; lower lemmas unawned or awned, awns 8-16(50) mm; lower paleas absent or hyaline and subequal to the lemmas; upper lemmas 4-4.5 mm long, 1.7-1.9 mm wide, elliptic; anthers 0.5-0.7 mm, purple. |
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Lower glumes | about 1/2 as long as the spikelets; upper glumes about as long as the spikelets; lower florets usually sterile, occasionally staminate; lower lemmas unawned, similar to the upper glumes; lower paleas subequal to the lemmas; upper lemmas 2.6-2.9 mm, not or scarcely exceeding the upper glumes, elliptic, coriaceous portion rounded distally, passing abruptly into a sharply differentiated, membranous, soon-withering tip; anthers 0.7-0.8 mm. |
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Caryopses | 1.2-1.6 mm, whitish; embryos 63-83% as long as the caryopses. |
2.7-2.9 mm long, 1.7-1.8 mm wide, elliptic in outline, mucronate; embryos about 75% as long as the caryopses; hila obovate. |
2n | = 54. |
= unknown. |
Echinochloa colona |
Echinochloa oplismenoides |
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Distribution |
AL; AR; AZ; CA; FL; GA; IL; KS; KY; LA; MA; MD; MO; MS; MT; NC; NJ; NM; OK; OR; PA; SC; TN; TX; VA; VT; WA; HI; PR; Virgin Islands
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AZ |
Discussion | Echinochloa colona is widespread in tropical and subtropical regions. It is adventive and weedy in North America, growing in low-lying, damp to wet, disturbed areas, including rice fields. The unbranched, rather widely-spaced panicle branches make this one of the easier species of Echinochloa to recognize. Hitchcock (1913) considered that 'colonum' was a non-declining contraction, but dictionaries of Linnaeus' time treated it as a declining adjective. Because Linnaeus was the first to name the species (as "Panicum colonum"), it seems best to follow the practice considered correct in his day; hence "E. colona". (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Echinochloa oplismenoides was first found in the United States, in southern Arizona, in 1993 (Fishbein 1995). It was previously known only from Mexico, with a range that extends from northwestern Mexico to Guatemala. The southern Arizonan plants were found near a cattle tank in wet grasslands. Fishbein stated that it was impossible to tell whether they represented a previously overlooked native species or an introduction. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 25, p. 398. | FNA vol. 25, p. 398. |
Parent taxa | Poaceae > subfam. Panicoideae > tribe Paniceae > Echinochloa | Poaceae > subfam. Panicoideae > tribe Paniceae > Echinochloa |
Sibling taxa | ||
Synonyms | E. colonum | |
Name authority | (L.) Link | (E. Fourn.) Hitchc. |
Web links |
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