Echinochloa muricata
Echinochloa oryzoides
American barnyard-grass, awn barnyard grass, rough barnyard grass
early barnyard grass, early water grass, rice field barnyard grass
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.
40-120 cm, erect, densely tufted;
nodes glabrous.
glabrous;
ligules absent;
blades 1-27 cm long, 0.8-30 mm wide.
glabrous;
ligules absent;
blades lax or drooping, 7-20 cm long, 4-12 mm wide, mostly glabrous.
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.
8-17(25) cm, lax, horizontal to strongly drooping, rachis nodes hispid, hairs to 4 mm, papillose-based, internodes glabrous;
primary branches to 5 cm, appressed to the rachises, mostly simple, glabrous or sparsely hispid, hairs to 3.5 mm, papillose-based, particularly at the nodes.
2.5-5 mm, disarticulating at maturity, usually purple or streaked with purple, usually hispid, hairs papillose-based.
3.7-7 mm long, 1.9-2.4 mm wide, disarticulating at maturity, broadly ovate to ovate.
usually 1/4 - 2/5 as long as the spikelets, occasionally 1/2 as long or longer;
upper glumes subequal to the spikelets;
lower florets sterile;
lower lemmas similar in size to the spikelet, usually awned, awns to 5 cm;
lower paleas well-developed;
upper lemmas 3.5-4.5 mm, similar in length and width to the upper glumes, broadly elliptic to ovate, with an acute, greenish tip;
anthers to 0.8 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.
1.9-3 mm, light brown or tan;
embryos 70-85% as long as the caryopses.
= 36.
= 54.
Echinochloa muricata
Echinochloa oryzoides
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 oryzoides is a common weed of rice fields throughout the world, growing in the flooded portions of the fields. It was included in E. oryzicola by Gould et al. (1972), but it differs in its shorter embryo, lax, strongly drooping panicle, and earlier (June-July) flowering period. This flowering period is also earlier than that of Oryza. In addition, E. oryzoides is usually conspicuously awned, having longer awns than even the awned variants of E. oryzicola, and it is rarely obviously pubescent on the cauline nodes, leaf sheaths, and collars. The earliest known collection of E. oryzoides in the United States was made in 1925 (Barrett and Seaman 1980).
(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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