Weeds
Centaurea depressa Bieb. - Depressed Cornflower.
Systematic position.
Family Asteraceae Dumort., genus Centaurea L.Synonyms.
Cyanus depressus (Bieb.) Sojak.Biological group.
Annual weed.Morphology and biology.
Plant depressed, cobwebby-woolly, up to 60 cm high. Stems rather rough, erect, ramified almost from base or somewhat higher; with branches slantwise upward directed, simple or little-ramified, rather rough. Basal and lower leaves entire with small lateral lobes, lanceolate, short-petiolate; upper leaves linear-lanceolate, sessile. Capitula medium-sized with ovate involucre, 10-12 mm wide, gathered in paniculiform or almost corymboid inflorescences. Marginal florets bright blue or blue-violet; middle florets fruit-bearing, violet. Achenes 5-6 mm in length with pappus 11-13 mm long, ovate, compressed, smooth, shining, greenish-ash-gray or light-brown. Flowering period May-July.Distribution.
Asia Minor, Iran, Afghanistan, India, Tibet; Crimea, the Caucasus, Central Asia.Ecology.
Plant prefers light, sandy-loamy soils, but can also grow on marly and clay soils.Economic significance.
Weed of grain crops and cotton; occurs in fallows, waste lands, abandoned grounds. Control measures include purification of seed grain, correct crop rotations, stubbling, early deep under-winter plowing, presowing soil cultivation, spring harrowing of winter crops, chemical weeding.Related references:
Bobrov E.G., Cherepanov S.K., eds. 1963. Flora of the USSR. V. 28. Moscow-Leningrad: AN SSSR, 656 p. (in Russian).Keller B.A., Lyubimenko V.N., Maltsev A.I., Fedtshenko B.A., Shishkin B.K., Rodzevich R.Yu., Kamenskii K.V., eds. 1935. Weed plants of the USSR. V. 4. Moscow & Leningrad: AN USSR, 416 p. (in Russian).
Nikitin V.V. 1983. Weed plants of the USSR flora. Leningrad: Nauka, 454 p. (in Russian).
Visyulina O.D., ed. 1970. Weeds of the Ukraine. Kiev: Naukova dumka, 508 p. (in Ukrainian).