Echinochloa crusgalli

Echinochloa crus-galli is a type of wild grass originating from tropical Asia that was formerly classified as a type of panicum grass. It is commonly known as cockspur (or cockspur grass), barnyard millet, water grass, common barnyard grass, or simply "barnyard grass" (which may refer to any species of Echinochloa or the genus as a whole however). This plant can grow to 1.5 m (4 ft 11 in) in height and has long, flat leaves which are often purplish at the base. Most stems are upright, but some will spread out over the ground. Stems are flattened at the base. The seed heads are a distinctive feature, often purplish, with large millet-like seeds in crowded spikelets. Considered one of the world's worst weeds, it reduces crop yields and causes forage crops to fail by removing up to 80% of the available soil nitrogen. It acts as a host for several mosaic virus diseases. Heavy infestations can interfere with mechanical harvesting. Individual plants can produce up to 40,000 seeds per year. W......read more on Wikipedia.