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a genus of plants of the family Leguminosae. The plants, which are often included in the genus Lathyrus, are perennial herbs with erect stems. The leaves are evenly pinnate and have a cusp at the apex. The flowers are gathered into a raceme. The fruit is a linear polyspermous pod.
There are about 30 species, distributed in the temperate zone of the northern hemisphere. Of the 22 species found in the USSR, the best known are the spring vetchling (O. vernus, or Lathyrus vernus) and O. gmelinii. The former grows in the European USSR, the Caucasus, and Siberia; it is encountered predominantly in mixed and broad-leaved forests, in glades, and amid thickets. Blossoming occurs in spring; the drooping flowers are initially purple and turn dark or light blue toward the end of blossoming. The spring vetchling yields a significant amount of nectar; it is also a valuable spring pasture plant. O. gmelinii, which grows in the Urals, Siberia, and Middle Asia, is eaten by cattle as pasturage and as hay. Many other species of Orobus are important forage crops.