Chenopodium album L. - Common lamb's-quarters.
Taxonomy.Family Chenopodiaceae Vent., Genus Chenopodium L.
Biology type.Spring annual weed.
Morphology and biology.Extremely polymorphic species. All parts of the plant are usually mealy farinose. Stem is up to 300 cm high, highly branched or simple, grooved, the base of leafstalks often has purple spots. Lower leaves are triangular with wedge-shaped base, middle leaves are rhomboid or oval-rhomboid, unequally dentated along the edge. Upper leaves are lanceolate, entire. Flowers are numerous, small, clustered in glomerules into spike-shaped inflorescences, which are aggregated into paniculate or racemose inflorescence. Productivity is up to 600,000 seeds per plant. Seeds are heterospermous, one plant produces three types of seeds: 1) larger-quickly germinated; 2) smaller-germinating in the second year after ripening; 3) very small seeds-germinating in the third year after ripening. Optimum temperature of seed germination is 20-30°C, the minimum is 3-4°C, maximum is 34-36°C. Seed germination is prolonged, it begins from early spring and lasts until autumn. Seedlings that appear in autumn do not over-winter. In southern regions plants begin to flower in May-June, bearing in June-July, in northern regions their flowering and bearing begins in July-August. Seeds remain viable even if submerged in water up to half a year, and also pass unharmed through the digestive system of animals. Seeds remain viable up to 10 years.
Distribution.Cosmopolite. This weed is found in all parts of the world. It abundantly spreads throughout the territory of the Former Soviet Union. In arctic and desert zones it is less common.
Ecology.This weed grows on all types of soils, preferring fertile ones. Nitrophil, extremely resistant to the fluctuations of soil acidity. Autochore, partially anthropochore, easy detached seeds infest soil as well as grain crops at harvest. Seeds are spread mainly by irrigation water and manure. Variable temperatures raise seed germinability. C. album is a pernicious segetal weed, especially in forest, forest-steppe and northern part of steppe zones. In southern part of steppe zone and in desert zone it is less abundant.
Economic value.It is the main non-specialized weed effecting practically all agricultural crops, vegetable gardens and orchards. C. album is common in ruderal places with rich fertile soils, near houses, in forest strips, along the roads and aryks (irrigation ditches). Control measures: careful cleaning of crop seeds, crop rotations with winter cereals, row crops and perennial fodder grasses. Early autumn plowing and timely spring tillage are recommended. In tilled crops - timely inter-row tillage, in uncultivated land - mowing of plants before flowering time.
Reference ctiations:Agaev M.G., ed. 1988. Main agricultural weeds in crops of Leningrad region. In: Catalogue of VIR world collection. Issue 468. Leningrad:VIR. 19-21 p.
Komarov, V.L. & B.K. Shiskhkin, eds. 1936. Flora of USSR. Moscow-Leningrad. V. 6: 61-63.
Nikitin V.V. 1983. Weeds in the flora of the USSR. Leningrad: Nauka. 160 p.
Ulyanova T.N. 1998. Weeds in the flora of Russia and other FSU states. Saint Petersburg: VIR. 213-214 p.
Zotova A.P. 1971. Weed plants and their control. Leningrad: Lenidzat. 78,80 p.