Barnyardgrass Echinochloa crus-galli (L.) Beauv.
Life cycle: Annual
Native status: Introduced from Eurasia.
Habitat: Crop fields and disturbed areas, prefers wet soils.
General description: Erect, up to 5 ft in height. Stems of mature plants are flattened at base. Seedhead is a branched panicle, with clusters of large seeds that often are reddish to maroon in color.
Key ID traits: Lack of ligule and hairless stems and sheaths.
Similar species: Barnyardgrass is the only weedy grass in Iowa without a ligule.
Miscellaneous: Another common name for barnyardgrass is watergrass due to its preference for wet areas. It is native to Eurasia, and in the same genus as several important grain crops, e.g. Japanese millet, white millet. Although there are no known herbicide resistant biotypes in Iowa, it has developed resistance to 8 herbicide groups and is a major weed of rice. It is an example of crop mimicry - in California biotypes in rice fields evolved so that there were identical in morphology to rice, thus farm workers involved in handweeding could not distinguish barnyardgrass seedlings from rice seedlings.