Weeds
Sherardia arvensis L. - Field Madder.
Systematic position.
Family Rubiaceae Juss., genus Sherardia L.Biological group.
Annual weed.Morphology and biology.
Plant 5-30 cm in height with thin, fusiform reddish root. Stalks outstretched-ascendant, tetrahedral, mostly branchy, sharply rough on edges. Leaves pointed with one vein, with fine spinules along margins. The lower leaves spatulate, gathered by 4 in a whorl; upper leaves lanceolate, gathered by 6 in a whorl. Flowers are collected by 6-8 in capitate semi-umbels, surrounded by involucre formed of 8-10 rigid, at base accrete leaflets. Bell with bend formed of 6 denticles covered with decumbent hairs, sometimes poorly appreciable. Corolla 4-5 mm in length, lilac or pink-lilac, seldom white, with a long tube and wide 4-lobed bend. Fruit is dry bipartite rough nutlet (about 4 mm in length), at top with six-dentate corona formed of former denticles of bell bend (sometimes visible as small tubercles only). Flowering May until September, fructifying in June.Distribution.
Almost all Europe, Asia Minor and Asia Anterior, Northern Africa, Canary islands; Northern America (adventive); the European part of the former USSR, the Caucasus, Central Asia (adventive), the Far East (adventive).Ecology.
Plant grows on clay hills, dry slopes, in forests in open places, in lawns, waste places, being common weed in fields, fallows, and orchards.Economic significance.
Weed litters crops, orchards, vineyards, tea plantations. Control measures include autumn plowing of ground, presowing cultivation, duly sowing, interrow treatments in plantings of tilled crops, maintenance of crop rotation; application of herbicides, if necessary.Reference citations:
Chesalin G.A. 1975. Weeds and their control. Moscow: Kolos, 256 p. (in Russian).Keller B.A., Lyubimenko V.N., Maltsev A.I., Fedtshenko B.A., Shishkin B.K., Rodzevich R.Yu., Kamenskii K.V., eds. 1935. Weed plants of the USSR. V. 4. Moscow & Leningrad: AN USSR, 416 p. (in Russian).
Nikitin V.V. 1983. Weeds in the flora of the USSR. Leningrad: Nauka, 454 p. (in Russian).
Shishkin B.K., ed. 1958. Flora of the USSR. V. 23. Moscow; Leningrad: AN SSSR, 776 p. (in Russian).