Lathyrus tuberosus L. - Pea Tuber
Systematic position.Family Fabaceae, genus Lathyrus L.
Biological group.Rhizome perennial plant.
Morphology and biology.Rhizome branchy, thin, with tuber-like thickened, spindle or almost spherical roots. Stems 25-100 cm in length, branched at base, rising or stretching, acute-edged, non-winged, with leaf tendrils; stipules semi-sagittate, 5-20 mm in length; leaf with costate non-winged petiole; petioles 8-14 mm length; leaf axis ending with tendril (usually branched in upper leaves); leaflet 1-paired, oblong-oval or oblong-obovate, obtuse, with pointed apex, 2.0-4.5 cm in length, 0.7-1.3 cm in width. Two lower leaves scale-like, first developed leaves dual, with subulate or semi-sagittate stipules. Pedicles sometimes somewhat curved, longer than leaf; raceme not thick, with 3-7 flowers; bracts lanceolate-subulate; pedicles almost as long as or longer than calyx; flowers 1.5-2 cm in length, purple-red, with a smell; calyx wide-campaniform; teeth of calyx as long as of shorter than tube. Flag pale-carmine. The flowers are strongly odorous. Beans bending downward, oblong-linear, almost cylindrical, naked, slightly swollen, 2.8-4 cm in length, 4-7 mm in width, yellowish-brown. Seeds 4-6 in number, 3-4 mm in diameter, spherical, squeezed laterally, dark-brown, almost smooth, punctuate; hilum linear, embracing 1/10th of seed; weight of 1000 seeds is about 12 g. The seeds germinate from depth of not more than 20 cm. The fresh-ripened seeds do no germinate. The seeds and tuber buds give shoots in April - May. VI-VIII.
Distribution.European part (mostly southern districts), the Caucasus, Western Siberia, Middle Asia. Outside the former USSR territory: Scandinavia (alien), Middle and Atlantic Europe, Mediterranean, Balkan Peninsula, Asia Minor.
Ecology.Inhabits steppes including fields, pastures and waste places as a weed, sometimes malicious one. Northward of the boundary of chernozems it is rarely found. In mountains it grows to 1800 m. It is a component of natural phytosystems on meadows and among shrubs in addition to fallows and sometimes crops. It prefers friable aerated soils.
Economic significance.In grain crops it is a malicious weed, especially after plowing-up hard fallow lands and steppes. It causes lodging of plants. Control measures are stubbling and deep plowing.
Related references.Artokhin, K.S. 2004. Atlas of weed plants. Rostov-na-Donu. 144 p. (in Russian).
Nikitin, V.V. 1983. Weed plants of the USSR flora. Leningrad: Nauka. 454 p. (in Russian).
Shishkin, B.K. & Bobrov, E.G., eds. 1948. Flora USSR. V. 13. Moscow; Leningrad: AN SSSR. 588 p. (in Russian).
Ulyanova T.N. 1998. Weeds in the flora of Russia and other CIS states. St. Petersburg: VIR. 233 p. (in Russian).
Volkov, A.N., ed. 1935. The regions of the distribution of the main weeds in the USSR. Moscow; Leningrad: Publishing House of Kolkhoz & Sovkhoz Literature. 153 p. (in Russian).