Echinochloa muricata
Echinochloa oryzicola
American barnyard-grass, awn barnyard grass, rough barnyard grass
late barnyard grass, rice barnyardgrass
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.
40-150 cm, erect or nearly so, densely tufted;
lower nodes usually antrorsely scabrous or villous;
upper nodes glabrous.
glabrous;
ligules absent;
blades 1-27 cm long, 0.8-30 mm wide.
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.
8-20 cm, erect to slightly drooping, rachis nodes hispid,with papillose-based hairs to 5.6 mm, internodes usually scabrous, sometimes also with a few papillose-based hairs;
primary branches to 4 cm.
2.5-5 mm, disarticulating at maturity, usually purple or streaked with purple, usually hispid, hairs papillose-based.
4-6 mm, ovoid to ellipsoid, disarticulating at maturity.
usually at least 1/2 as long as the spikelets;
upper glumes equaling or exceeding the upper florets;
lower florets sterile;
lower lemmas often thickened and somewhat coriaceous, unawned or awned, awns to 1.5 mm;
lower paleas well-developed;
upper lemmas broadly ovate to elliptical, coriaceous portion rounded distally, passing abruptly into an early-withering, acuminate, membranus tip that is further demarcated from the coriaceous portion by minute hairs (use 25x magnification);
anthers 0.9-1.2 mm.
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.
1.2-2.5 mm, broadly obovoid or spheroid, yellowish;
embryos 1.4-2 mm, 80-91% as long as the caryopses.
1.7-2.6 mm, brownish;
embryos 89-98% as long as the caryopses.
sheaths densely pubescent;
upper sheaths glabrous or pubescent at the throat, and sometimes on the collar;
ligules absent;
blades stiff, ascending, lower blades pubescent, upper blades usually glabrous.
= 36.
= 36.
Echinochloa muricata
Echinochloa oryzicola
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.)
Like Echinochloa oryzoides, E. oryzicola is an introduced weed of rice fields, where it grows in the flooded portion, with the rice. The two are quite distinct, with E. oryzicola flowering after Oryza and having a longer embryo and an erect panicle. It is also more likely to have evidently pubescent cauline nodes, leaf sheaths, and collars than E. oryzoides and is never conspicuously awned.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Spikelets 2.5-3.8 mm long; lower lemmas unawned or awned, the awns to 10 mm long | var. microstachya |
1. Spikelets 3.5-5 mm long; lower lemmas usually awned, the awns 6-16 mm long | var. muricata |
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