Hordeum pusillum
Hordeum pusillum, the little barley, is an annual grass native to the United States. It arrived via multiple long-distance dispersals of a southern South American species of Hordeum about one million years ago. Its closest relatives are therefore not the other North American taxa like meadow barley or foxtail barley, but rather Hordeum species of the pampas of central Argentina and Uruguay. It is less closely related to the Old World domesticated barley, from which it diverged about 12 million years ago. It is diploid.Uses
The tiny seeds are edible, and this plant was part of the Eastern Agricultural Complex of cultivated plants used in Pre-Columbian times by Native Americans. Before being displaced by maize agriculture, little barley may have been domesticated. Today it can be found in grassland, Sonoran desert, at the edges of marshes, as well as ruderal habitats like roadsides.