Weeds
Xanthium sibiricum Patrin ex Widd. - Siberian Cocklebur
Systematic position.
Family Asteraceae, genus Xanthium L.Synonym.
Xanthium japonicum auct.Biological group.
This is an annual spring weed.Morphology and biology.
Stem 40-60 cm tall, straight, rigid, simple or somewhat branchy, rounded below, striated upwardly. Leaves are triangular-ovoid or cordate, 5-9 cm long, almost entire or indistinctly irregularly serrate-dentate, with fine thin decumbent hairs or bristly pubescent on both sides; petioles are 11 cm long. Involucre embracing hemicarp, oval or ellipsoid, narrowing basad, swollen, 12-15 mm long and 4-7 mm wide, with glandular pubescence; regularly covered with short (1-2 mm long) and thin, hardly thickened at base and hooked at apex, yellowish or greenish thorns. Involucral apical beaks are mostly straight, seldom crescent, sharp, frequently unequal, parallel, less often converging, pubescent, 1.5-2.5 mm long. Blossoming and fructifying occurs from July until September.Distribution.
The Caucasus, Western and Eastern Siberia, the Far East, Central Asia, northern Iran, Kashmir, China, Japan.Ecology.
The plant grows along river banks and valleys, in meadows, edges, waste grounds and dumps, near habitations. It grows well on fertilized grounds.Economic significance.
The weed litters crops of soya, maize, vegetable cultures. Control measures include autumn plowing, pre-seeding treatment of grounds, cleaning of sowing material, two or three harrowings during the shooting stage of soya, inter-row treatments of tilled cultures, application of herbicides if necessary, maintenance of crop rotation.Reference citations:
Komarov, V.L., ed. 1959. Flora of the USSR. V. 25. Moscow-Leningrad: AN SSSR. 631 p. (In Russian)Korchagina V.A., Penchukov V.M., Morozov N.A., Smashevskaya G.A., Kolomiitsev F.B., Trubeeva A.I., Baranova M.M. 1972. Control of weeds in the Far East. Khabarovsk: Khabarovsk Publishing House. 160 p. (In Russian)