Weeds
Lactuca tatarica (L.) C.A.Mey. - Tatar Lettuce, Blue Lettuce.
Synonyms.
Sonchus tataricus L., Mulgedium tataricum (L.) DC.Systematic position.
Family Asteraceae (Compositae), genus Lactuca L.Biological group.
Perennial plant that forms offshoots.Morphology and biology.
Root is vertical, with numerous horizontal lateral rhizomes, which generate new stalks. Stalk is glabrous or with white pubescence, simple or ramified, 25-80 (up to 115) cm in height. The leaves are collected at the lower part of stalk. They are sedentary, coarse, narrowed at base, gray, with sparse marginal prickles. Leaves 5-18 cm in length and 0.5-5 cm in width. The lower and middle leaves are runcinate or pinnatilobate with narrow lobes. The upper leaves are full, lanceolate, almost sessile. Inflorescence is a spreading panicle. Peduncles short, with fine leaflets. Calathidia are 2.5-3 cm in diameter. Receptacle bare. Flowers dark blue or violet, with ligules 10 mm in length and 2.5 mm in width. Involucre cylindrical, quadriseriate, 11-16 mm in length and 3-5 mm in width, pubescent from the outside. Hemicarps are 6 mm in length, slightly compressed, with 5-7 longitudinal ribs, almost black. They are densely pubescent. Rostellum is half as long as the hemicarp. The pappus is 9-12 mm long; composed of white, soft, and easily falling hairs; with sharp-dentate ringlet at base. Plants contain white lacteal juice. Blossoming occurs from July to August. Reproduction occurs by seeds and cloning. Its rhizomes are fragile, easily producing roots. The plant is capable of producing about 6000 seeds that maintain viability for 4 years. Optimum temperature for seed germination is +20-30°C. Shoots appear in spring and autumn.Distribution.
It is a polyzonal Eurasian species. The general distribution area includes Western Europe, Northern Central Asia, and Japan. In the former USSR, it occurs in the European region, the Caucasus, Central Asia, and southern Siberia. In the Far East, it has occurred as an adventive plant from the second half of the 20th century.Ecology.
It is distributed throughout forest-steppe, steppe and semi-desert areas. The plant is resistant to drought, salinization and packing of soil. In nature, it grows in meadows, in steppes and semi-deserts, as well as in salty soils, for example, along sea coasts. It is also found in rubbish heaps (waysides of railroads and roads) and in fields.Economic significance.
Widespread segetal weed. In steppe and forest-steppe, it mainly litters grain crops, as well as all crops in semi-desert and desert zones. Agronomic recommendations are as follows: Regularly destroy rhizomes and seeds of the weed with the help of appropriate types of soil treatments and herbicides. Do not contaminate sowing material or soil with seeds of the Lettuce. Mow off or pull up the weed before fructification. Control measures include deep plowing, correct crop rotation and the clearing of weeds from fallow lands and field edges. Thus, experts recommend deep plowing in April and the cleaning of arable lands and field edges.Related references:
Cherepanov S.K. 1995. Vascular plants of Russia and adjacent states (of the former USSR). Saint-Petersburg: Mir i semya-95. 991 pp. (in Russian).Fisyunov A.V. 1984. Weeds. Moscow: Kolos. 320 pp. (in Russian).
Keller B.A., Lyubimenko V.N., Maltsev A.I., etc. (Eds.) 1935. Weed plants of the USSR. Moscow & Leningrad: AN SSSR. Vol. 4. 414 pp. (in Russian).
Kharkevich S.S. (Ed.) 1992. Vascular plants of the Soviet Far East. Saint Petersburg: Nauka. Vol. 6. 428 pp. (in Russian).
Krasnoborov I.M. (Ed.) 1997. Flora of Siberia. Novosibirsk: Nauka. Vol. 13. 472 pp. (in Russian).
Maevskii P.F. 1954. Flora of middle belt of the European part of the USSR. Moscow & Leningrad: Selkhosgiz. 912 pp. (in Russian).
Maltsev A.I. 1937. Atlas of the major species of weed plants of the USSR. Moscow & Leningrad: Selkhosgiz. Vol. 1. 168 pp. (in Russian).
Ulyanova T.N. 1998. Weed plants in flora of Russia and other CIS countries. Saint Petersburg: VIR. 233 pp. (in Russian).