Weeds
Scleranthus annuus L. - German Knotgrass
Systematic position.
Family Caryophyllaceae Juss., genus Scleranthus L.Synonyms.
Scleranthus polycarpos L.Biological group.
Annual weed.Morphology and biology.
Stem pubescent, strongly branchy from base, 10-15 cm long. Leaves without stipules, linear, pointed. Flowers green, sedentary, located on branch ends and in sheaths of upper leaves. Calyx bell-shaped, half-dissected into 5 triangular white-limbated lobes. The calyx at fruits hardens and falls down together with fruits. Corona is absent. Five of the 10 stamens are sterile. Fruits unilocular, indehiscent. Blossoms June until September.Distribution.
Everywhere in the European part of the former USSR except for the Far North, all areas of the Caucasus. Adventive species in the Far East.Ecology.
The species grows mainly on sandy ground. In taiga zone, it occurs on fields in all cultures. In forest-steppe and steppe zones, it loses value of a segetal plant, becoming a ruderal plant along roads, in fallow lands and other waste places, pastures, and on stony slopes.Economic significance.
The weed litters crops of winter (rye, wheat) and spring (barley, oat) cereals, fallows, plantations of potato, kitchen gardens, sometimes clover. In taiga zone in crops winter rye, it can form dense cover under cultural plants. Control measures include crop rotation, hand and chemical weeding.Reference citations:
Geideman T.S. 1954. Keys to plants of Moldavian SSR. Moscow & Leningrad: Nauka, 466 p. (in Russian).Nikitin V.V. 1983. Weeds in the flora of the USSR. Leningrad: Nauka. 454 p. (in Russian).
Tolmachev A.I., ed. 1962. Keys to vascular plants of Komi SSR. Moscow & Leningrad: AN SSSR, 360 p. (in Russian).
Tolmachev A.I., ed. 1976. Flora of Northeast of the European part of the USSR. V. 2. Leningrad: Nauka, 316 p. (in Russian).
Zernov A.S. 2002. Keys to vascular plants of the north of Russian Black Sea coast. Moscow: KMK, 284 p. (in Russian).