Weeds

Amethystea caerulea L. - Blue Amethystea.

Systematic position.

Family Lamiaceae, genus Amethystea L.

Biological group.

Annual germiniparous weed.

Morphology and biology.

Plant is 10-70 cm tall, stem is erect, ramified, tetrahedral, usually bluish-violet, covered with short glandular hairs located mainly in internodes and at the top. Leaves are 2-6 cm long, 1-3 cm wide, hairless, deeply 3-5-sectional, with lanceolate dentate lobes, cuneately narrowing at base, with short petiole; the under side is more pale. Inflorescence is spreading, paniculate. Calyx is hairless or has sparse glandular hairs, bluish, rounded-belled, cut by half into sharp lanceolate teeth. Corolla is blue, 5-lobed, longer than the calyx, 3-3.5 mm long. Middle lobe of lower labium is bigger than other ones, obovate. Two stamens are longer than the corolla. Seeds are about 2 mm long, obovate, triquetrous, gray-brown, brown, reticulate-wrinkled. Flowers in June-September.

Distribution.

Iran, Mongolia, Northern China. Western Siberia, Eastern Siberia, the Far East, Central Asia.

Ecology.

Plant requires light and does not stand flooding well. In old waste-lands it grows sparsely, dying because of soil consolidation.

Economic significance.

Weed of grain and tilled crops, vegetables, soy, fodder grasses; occurs in kitchen gardens, waste lands, along roads, near inhabited areas. Control measures include early removal of the stubble followed by deep under-winter plowing, inter-row cultivation of tilled crops, chemical weeding.

Reference citations:

Buch T.G., Kachura N.N., Shvydkaya V.D., Andreeva E.R. 1981. Weed plants of the Primorskii Territory and their control. Vladivostok: Dal'nevostochnoe Publishing House. 243 p. (In Russian)
Keller B.A., Lyubimenko V.N., Mal'tsev A.I., Fedchenko B.A., Shishkin B.K., Rozhevits R.Yu., Kamenskii K.V., eds. 1934. Weed plants of the USSR. V. 4. Leningrad: AN SSSR. 414 p. (In Russian)
Nikitin V.V. 1983. Weed plants of the USSR flora. Leningrad: Nauka. 454 p. (In Russian)
Shishkin, B.K. & S.V. Yusepchuk, eds. 1954. Flora of the USSR. V. 20. Moscow-Leningrad: AN SSSR. 556 p. (In Russian)
Ulyanova T.N. 1998. Weed plants in the flora of Russia and other CIS states. St. Petersburg: VIR. 344 p. (In Russian)

© Sokolova T.D.

 

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