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)