Seedling
Seedling leaves narrow, rough, ribbed. Sheaths smooth to hairy, ribbed, but not rough.
Mature plant
Stems are erect, 1 to 2 feet tall at maturity, growing in clumps.
Leaves have short ligules and slightly clasping auricles. Ligules with scalloped edges. Leaf blades rough, ribbed, with hairs on inner and outer surfaces. Sheaths hairy or hairless, ribbed, but not rough.
Root structure description
Fibrous, dense, perennial.
Flowers
Flower heads are bushy spikes, about 2 to 4 inches long, with awns about 2 inces long. Awns yellow-green to purple. Spikes nodding, break up readily when mature. Flowers in July. Seeds 1/10 inch long, hair and yellow. The awns of foxtail barley are barbed and cause irritation to the eyes, throats and noses of livestock.