WILD OAT, Avena fatua L. 1, panicle; 2, portion of lower stem, crown, and roots; 3, 4, seeds with hull and enlargement of "sucker-mouth" base; 5, kernel without hull. Annual, reproducing by seed. Root system extensive and fibrous. Stems smooth, stout, 1 to 4 feet (0.3 to 1.2 m) high. Leaves 3 to 8 inches (7.5 to 20 cm) long, resembling those of tame oats. Panicle usually more open than that of tame oats. Spikelets distinguished by long, dark awns, the lower parts twisted, the upper parts bent sharply at right angles to twisted parts. Seeds vary from white to yellow, brown, gray, or black; are usually hairy, especially near base. Distinguished from cultivated oats by the round "sucker-mouth" callus at base of the grain. Seeds usually ripen earlier than most cereals and many drop to ground before time to harvest cultivated cereals. Found especially in fields under continuous cropping to small grains and flax. Probably the most harmful annual weed in the hard red spring wheat area. Recently it has become a problem in the southern part of the hard red winter wheat area, where it acts as a winter.