Vicia tetrasperma (L.) Moench - Vetch Tetra-Seed.
Systematic position.Family Fabaceae, genus Vicia L.
Synonym.Ervum tetraspermum L.
Biological group.Annual spring-summer plant.
Morphology and biology.Plant almost bare, 20-50 cm high; stems are thin, weakly clutching, strongly branched. Leaves usually terminated with branched tendril. 3-4 (5) pairs of leaflets; leaflet linear-oblong or linear, 5-20 mm in length, 1-2.5 (3) mm in width. Flowers 1-2 in number, situated on peduncle, small, 5-6 mm in length; calyx is shorter than corolla; teeth of the calyx are triangular-lanceolate; lower teeth longer, exceeding half length of tube. Corolla is whitish, with lilac flag and blue wings. Fruits are beans, located on short stalks, oblong or linear, 8-12 (15) mm in length, about 3.5 mm in width, flat, bare, having 4 seeds (very rarely 3 or 5 seeds). The seeds are spherical, brown. Flowering since May till July.
Distribution.Europe, Asia, North America (adventive); as a weed, adventive all over the globe.
Ecology.Fields, rarely meadows, shrubs, sides of roads.
Economic significance.Weed of spring crops (cultures of the cereals). Control measures include harrowing of young crops, duly interrow treatments.
Related references:Keller B.A., ed. 1934. Weed plants of the USSR. V. 3. Leningrad: AN SSSR. 448 p. (in Russian).
Komarov V.L., ed. 1948. Flora of the USSR. Moscow & Leningrad: AN SSSR. V. 13: 410-411. (In Russian)