A number of important cultivated varieties of both winter and spring habit are included in this species. In red oats the two flowers in the spikelet adhere tightly to each other and separate by fracture of the rachilla or stem at the base. The lemmas adhere to the kernel and have weak, non-twisted awns. Stems are usually slender and rather stiff and reddish in color. Panicles are small, narrow and erect with relatively few spikelets.
Glumes are somewhat longer than in common oats.
Red oat varieties are the kinds generally grown in the southern half of the United States. A. wiestii Steud. This species, introduced into this country for study, appears native to the Eastern Mediterranean Area. Stems'are slender, medium high, and stiff. It differs from the wild oat, A. fatua L., in having shorter, more slender lemmas that terminate in two bristle-like glume points.