Hordeum pusillum

First described in 1818 and 1887 by Thomas Nuttall, Hordeum pusillum is an annual grass and a member of the Poaceae (grass) family. Hordeum pusillum, also known as "little barley," is a member of the subfamily Festucoideae. The plant itself can is approximately 14-40 centimeters tall and is self-fertilizing.[5] Hordeum pusillum leaves and spikelets alternate. The flat and pubescent leaves can range anywhere from 2.4 to 12.7 cm in length and 2.0 to 4.5 mm wide. The sheath of little barley can be either glabrous or pubescent and wraps loosely around the stem.[6] The inflorescence ranges between 4-8 cm long. Of the three alternating floral spikelets, only one is fertile. The plant's growth period is during the winter months, producing mature grains by April.[5] The roots are fibrous, and the mark of a mature spikelet is when they turn a tan to brown color. The stems changes from a bluish-green color to brown as the plant matures.[7] It grows best in a sunny, dry and gravely locations.[6]

Little barley germinates best when exposed to light, and experiences best germination after one to two weeks of prechilling, anymore than that and the viability of seeds decreases over time. After two weeks of prechilling, little barley seeds go into dormancy, allowing little barley to overwinter and come back year after year. Seeds germinate best at 17 and 20 degrees C. The more mature the seeds, the better they germinate.[8]

Little barley is an annual flowering monocot, in general wheats are self-pollinating and pollinated by wind. Pollination occurs during the winter through the summer.[9] The center spikelet is fertile whilst the lateral spiklets are male and infertile.

Hordeum pusillum is native to the majority of North America, mainly the United States of America and parts of Canada.[10] It is found commonly on roadsides, ditches, and disturbed areas.[11]

Little barley can suppress the growth of more desirable forage grasses. Little barley is best controlled prior to its dormancy in the fall or early spring, and can be further controlled through the use of the herbicides such as Gramoxone, Olympus, Maverick, or Accent. Spring usage of herbicides has also been found effective at controlling the growth of little barley, in pastures, however; late winter/early spring treatment with Accent has been found effective. Prolonged usage of herbicides can result in higher tolerance.[12]

Common names little barley and little wild barley. Hordueum comes from the latin word horreō, horrēre "to bristle " and pusillum is the "nominative neuter singular of pusillus"- "very little, very small, tiny."

Hordeum pusillum herbarium sheet

Little barley is believed to have been cultivated by Native Americans due to its general abundance. Earliest known cultivation in North America occurred in Louisa County, Iowa. It was found alongside domesticated goosefoot seeds and squash/gourd rinds. In order to cultivate little barley, large plots were required due to the grain's small size. Little barley cultivation is important in understanding pre-maize agriculture.[13]Hordeum pusillum was briefly domesticated during the Prehispanic period. Evidence suggests domestication took place in the southeastern and southwestern United States. In the southeastern and midwestern United States, however; domestication lasted through the Middle Archaic and protohistoric periods.[5] To the Hohokam culture, archeological evidence suggests that little barley was used for trade between other tribes whose diet did not normally included domesticated little barley.[5]

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 agriculture based on maize, 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.[1][14]

The grains would be dried, processed, and then cooked before eating.[5] Cultivated for its edible grains, it is also classified as a cereal grain. Little barley seeds have an awn, a sharp hair-like attachment on the grain, which was then separated from the grain and possibly parched, roasted, and boiled. The seeds are nutritious and starchy.[13] 100 grams of little barley constitutes almost 24.3 percent of carbohydrates, 22.4 percent of protein, 18 percent of calories, and 5-6 percent of fiber and fat of a recommended daily 2,000-calorie diet.[5]

Little barley is a known mild allergen, people displaying an allergy to Hordeum pusillum may also exhibit an allergy towards other wheats.