Weeds
Sigesbeckia orientalis L. - Indian Weed.
Taxonomic position.
Family Asteraceae, genus Siegesbeckia L.Synonyms.
Sigesbeckia orientalis subsp. caspica (Fisch. & C.A. Mey.) Kitam.Biological group.
Annual late spring weed.Morphology and biology.
Plant reaches 30-100 cm in height. Stem straight, simple or dichotomously ramified, costate; curly-pubescent, particularly in the upper part. Leaves opposite, triangular-ovoid or ovoid, rounded or sharply-cordate at base and narrow-cuneiform toward petiole, sharp or pointed at apex, irregularly dentate along margin, with decumbent hairs (from below especially), with sparse fine glandules, sometimes with fine swollen tubercles. Anthodium is small, about 5 mm in width; external leaflets of involucre are covered with dense capitate pedunculate hairs, obovate, much longer than internal leaflets. Hemicarp (3 mm in length and 1.2 mm in width) inversely pyramidal, dark gray or mat-black, sometimes with sparse lighter amorphous tubercles, with white circular welt at apex. Marginal hemicarps slightly bent. Blossoming occurs from June until August, fructifying from July until September.Distribution.
Subtropics and tropics of Old World, North America, China, Middle East. In the former USSR: the Black Sea coast, Crimea, the Caucasus, the Far East, Central Asia.Ecology.
Grows in garbage places, waste grounds, dumps, along roads, fences and buildings, in gardens, parks, kitchen gardens, fallow lands, along banks of channels and irrigation ditches. The plant is a hygrophile and thermophile.Economic significance.
Litters crops of tilled cultures mainly. Control measures include stubbling, autumn plowing, pre-seeding treatment of ground, inter-row treatments, application of herbicides if necessary, maintenance of crop rotation.Reference citations.
Chesalin, G. A. 1975. Weeds and their control. Moscow: Kolos. 256 p. (in Russian).Komarov, V. L., ed. 1959. Flora of the USSR. Moscow & Leningrad: AN SSSR. V. 25: 631 p. (in Russian).
Nikitin, V.V. 1983. Weeds in the flora of the USSR. Leningrad: Nauka. 454 p. (in Russian).
Ulyanova, T.N. 1998. Weeds in the flora of Russia and other CIS states. St. Petersburg: VIR. 233 p. (in Russian).