Weeds
Lappula squarrosa (Retz.) Dumort - European Stickseed
Systematic position.
Family Boraginaceae, genus Lappula Moench.Synonyms:
Myosotis squarrosa Retz., Lappula echinata Gilib., Lappula myosotis Moench, Echinospermum lappula Lehm.Biological group.
It is a biennial, less often annual weed.Morphology and biology.
Stem covered with gray hairs, 30-80 cm tall, branchy in upper part. Leaves lanceolate, in upper part linear-lanceolate, more or less densely hairy; the hairs erect. Inflorescence is a short panicle. Pedicels are shorter than calyx, sticking upward at fruits. Flowers are small (2-3 mm in diameter); corolla blue, with foveate bell-shaped bend. Fruit is an almost spherical nutlet, covered with multiseriate spinules; the latter are not coalesced at base, having anchor-like apices. Fruits germinate at temperatures ranging from 6-8 to 36-38°C; optimum is 22-28°C. Shoots appear in April-May, and in August-September; autumn shoots over winter. Maximal fruitfulness is 1500 seeds. Seeds maintain their viability for 5 years.Distribution.
The species is widely distributed throughout moderate and cold zones of Europe and Asia, brought to and naturalized in Northern America and Southern Africa. It grows in all areas of the European part of Russia and CIS countries (except Arctic regions), in the Caucasus, Western and Eastern Siberia, the Far East (seldom). It is a common plant in all areas of Central Asia.Ecology.
The species occurs in dry stony places, garbage places, at dwellings, on overgrazed pastures, fallow and abandoned lands, and among crops of steppe zone. It grows less often north and south of the steppe zone. It prefers warm and dry habitats as well as easy fertile soils.Economic significance.
The weed contaminates grain crops, especially winter cereals and pastures in steppe zone. The main control measure is double stubbling by a hard disk harrow along with subsequent plowing.Reference citations:
Bazdyrev G.I., Zotov L.I., Polin V.D. 2004. Weed plants and their control in modern agriculture. Moscow: MSKHA. 288 p. (In Russian)Gubanov I.A., Kiseleva K.V., Novikov V.S., Tikhomirov V.N. 2004. The illustrated keys to plants of Middle Russia. V. 3. Moscow: KMK. 520 p. (In Russian)
Keller B.A., ed. 1934. Weed plants of the USSR. V. 3. Leningrad: AN SSSR. 448 p. (In Russian)
Nikitin V.V. 1983. Weeds in the flora of the USSR. Leningrad: Nauka. 454 p. (In Russian)
Tolmachev A.I., ed. 1974. Keys to higher plants of Sakhalin and Kurile islands. Leningrad: Nauka. 372 p. (In Russian)