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awnless barnyard grass, jungle rice, jungle ricegrass, or jungle-rice, small barnyard grass, watergrass

creeping river grass

Habit Plants annual; erect or decumbent, cespitose or spreading, rooting from the lower cauline nodes. Plants perennial; not rhizomatous.
Culms

10-70 cm;

lower nodes glabrous or hispid, hairs appressed;

upper nodes glabrous.

1-2 m tall, to 1 cm thick, erect or decumbent and rooting at the lower nodes, upper portion sometimes floating distally;

nodes glabrous or antrorsely villous.

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.

mostly glabrous, minutely puberulent, or hispid, hairs papillose-based, throat hispid;

ligules present on the lower leaves, 1-5 mm, of stiff hairs;

blades 15-70 cm long, 5-13 mm wide, glabrous.

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.

13-45 cm, erect, rachis nodes hispid, hairs 3-6.5 mm, papillose-based, internodes scabrous;

primary branches 4-10 cm, subverticillate, ascending, nodes hispid, hairs 2.5-4 mm, papillose-based, internodes scabrous;

secondary branches short, spikelets subsessile, in clusters.

Spikelets

2-3 mm, disarticulating at maturity, pubescent to hispid, hairs usually not papillose-based, tips acute to cuspidate.

4-7 mm, hispid, hairs appressed, disarticulating at maturity.

Caryopses

1.2-1.6 mm, whitish;

embryos 63-83% as long as the caryopses.

to 3 mm.

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.

glumes at least 1/2 as long as the spikelets;

lower florets staminate;

lower lemmas apiculate or awned, awns to 18 mm;

lower paleas subequal to the lower lemmas, often purple;

anthers of lower florets 1.5-3.6 mm, orange;

upper lemmas 2.5-5 mm, elliptic or narrowly ovate, apices obtuse, with a membranous, soon-withering tip;

anthers of upper florets shorter than those of the lower florets.

2n

= 54.

= 54.

Echinochloa colona

Echinochloa polystachya

Distribution
from FNA
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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from FNA
FL; LA; TX; PR
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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 polystachya grows in coastal marshes, often in standing water, from Texas, Louisiana, and Florida south through Mexico and the Caribbean islands to Argentina. Two varieties exist. Echinochloa polystachya var. polystachya has glabrous culms and leaf sheaths; Echinochloa polystachya var. spectabilis (Nees ex Trin.) Mart. Crov. has swollen, pubescent cauline nodes and pubescent leaf sheaths.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 25, p. 398. FNA vol. 25, p. 394.
Parent taxa Poaceae > subfam. Panicoideae > tribe Paniceae > Echinochloa Poaceae > subfam. Panicoideae > tribe Paniceae > Echinochloa
Sibling taxa
E. crus-galli, E. crus-pavonis, E. esculenta, E. frumentacea, E. muricata, E. oplismenoides, E. oryzicola, E. oryzoides, E. paludigena, E. polystachya, E. pyramidalis, E. walteri
E. colona, E. crus-galli, E. crus-pavonis, E. esculenta, E. frumentacea, E. muricata, E. oplismenoides, E. oryzicola, E. oryzoides, E. paludigena, E. pyramidalis, E. walteri
Synonyms E. colonum
Name authority (L.) Link (Kunth) Hitchc.
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