Weeds
Artemisia desertorum Spreng. - Desert Wormwood
Systematic position.
Family Asteraceae (Compositae), genus Artemisia L.Synonyms.
A. japonica Thunb. f. manshurica Kom., A. manshurica (Kom.) Kom., Oligosporus desertorum (Spreng.) Poljak. Now some scientists divide {share} two species A. desertorum Spreng. ЁA. manshurica (Kom.) Kom.Biological group.
This is a summer-green perennial rhizomatous plant.Morphology and biology.
The plant is glabrous and green. Rootstock (rhizome) is woody, short, and thick, with numerous additional roots, developing vegetative and generative runners. Stems are 40-90 cm tall, direct, thin, ribbed, single or not numerous, branchy in the upper part. Color is from bright-brown to red-violet. Fruitless (vegetative) runners sometimes are at the base of generative runners. Basal and lower leaves are long-petioled, variable in size and lobing, usually 4-10 cm long, 2-3- pinnatipartite into lanceolate segments, each of which terminates in three sharp teeth. Middle and upper leaves are gradually smaller, shortly petiolate to sessile, basally auriculate, 3-5 cm long, uni- pinnatipartite into 3-7 linear acute segments. The uppermost leaves are simple, fine, linear, and acute. Inflorescence is a narrow compressed panicle. Calathidiums are numerous, heterogamic, pedunculate, sub- globose or widely ovoid, 2-2.5 mm long and 1.5 mm wide. Involucral leaflets are smooth, glabrous, 6-7 in number. External leaflets are oval, internal are long. Receptacle is bare. Marginal pistillate flowers are 3-4 in number, with narrowly tubular nimbus. Middle staminate flowers are 5-6 in number with narrowly conic nimbus. Achenes are 0.5 mm long, ovoid, brilliant. Color is from black to dark-brown. The plant blossoms in August.Distribution.
The species was described to be from Siberia. Type is deposited in Berlin. General distribution includes the areas of Pakistan (Kashmir, Ladakh), India, China, Mongolia and Russia (Eastern Siberia, the south of the Far East). In the territory of the former USSR the species is distributed accordingly: Eastern Siberia (Angaro-Sajany and the Southern-Buryatiya floristic areas, also the Chita area) and the Far East (Dauriya, Nizhnyaya-Zeya, Bureya, Amgun, Ussuri districts).Ecology.
The species grows on dry stony slopes, in meadow and steppe, in light forest (larch, pine, birch), on river terraces, in bottomlands, on sandy deposits.Economic significance.
This plant litters crops in the Far East. For many years it was found in long-term deposits as the main cover plant, less often in young deposits, even less often in grain crops and soya as demonstrated by Shishkin (1936) and Nikitin (1985). However at the end of the 20th century, scientists have noted a sharp increase of the role of this plant in the contamination of crops. From a category of permanent weeds, the species passes into the category of the basic weeds of grain, in soya and other vegetable cultures in the south of the Far East (Ulyanova, 1998). Its occurrence and abundance in crops increases annually. Control measures includes regular destruction of the wormwood rhizomes with the help of appropriate types of soil treatment and herbicides; avoiding contamination of sowing material or ground by seeds; mowing-off or pulling-up the weed before fructification.Reference citations:
Bobrov, E.G. & N.N. Zvelev, eds. 1961. Flora of the USSR. V. 26. Leningrad - Moscow: AN SSSR. 940 pp. (In Russian)Kharkevitбh S.S., ed. 1992. Vascular plants of the Soviet Far East. Saint-Petersburg: Nauka. V. 6. 428 pp. (In Russian)
Nikitin V.V. 1983. Weed plants of the USSR flora. Leningrad: Nauka. 454 pp. (In Russian)
Shishkin I.K. 1936. Weed plants of southern part of the Far East. Khabarovsk. 144 pp. (In Russian)
Ulyanova T.N. 1998. Weed plants in flora of Russia and other FSU countries. Saint Petersburg: VIR. 233 pp. (In Russian)