Source: Magness et al. 1971
The vetches are weak-stemmed, semi-vining plants with pinnate leaves terminating in tendrils. Some 150 species are known, about 25 of which are native in the United States. However, the species grown agriculturally here are all introduced, being native to Europe or westem Asia. The vetches are extensively used as green manure for soil improvement, for hay, and in the South for winter pasture. Vetch seed is harvested from more than 100,000 acres annually (112,956 acres in 1959, census figure) in the United States - sufficcient to seed around 1,000,000 acres. Vetches may become troublesome weeds in grain fields but are readily controlled with herbicides. Tares as mentioned in the Bible are believed to have been common vetch.