Wild oats (Avena fatua) belongs to Poaceae (the Grass family). It is an annual herb that is native to Europe. Nowadays, it is naturalized in temperate areas worldwide. This herb grows in fields, grasslands, streambanks or roadsides, and can reach 30-100 cm in height. The stems are erect, fasciculate and midair. The leaves are linear and 10-30 cm long. The panicle is borne and produce the greenish spikelets from May to July. The spikelet is composed of 2-3 floscules with long aristae.