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Elymus repens (L.) Gould |
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Graminae Agropyron repens (L.) Beauv., Elytrigia repens (L.) Desv. ex Nevski |
Author: Alain Peeters |
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Couch or twitch or quackgrass (English), Chiendent commun (French), Gemeine queeke (German). Perennial plant, robust, more or less densely hairy, very rhizomatous. Stems erect, 30 - 120 cm high. Long or very long rhizomes. Blade rolled when young, large, flat, green or bluishgreen, rough (rub from the top to the bottom), more or less hairy on the upper part. Sheath of the inferior leaves often very densely hairy. Ligule very short. Auricles narrow, quite short, sharp, variable. Spike-like inflorescence, long, with densely overlopped spikelets. Spikelets with 5-10 flowers, often aristate, compressed, applied on the stem by their broader side. Glumes and lemma aristate or pointed. Very variable species. The weight of 1000 seeds is 2.0 to 2.5 g (average seeds). Chromosome number: 2n = 42 (hexaploid). Other chromosome numbers have also been observed: 2n = 28 or 35 or 56. Physiological peculiarities: Couch is one of the latest grass. It heads after timothy. Widespread in the climates of the temperate areas. Very resistant to cold and heat. Very resistant to drought. Large range from dry to wet soils. Optimum on nutrient rich soils (euthropic species), neutral, slightly acid or basic. Large range of soil texture: can be abundant on peat soil or on shallow mineral soils if they are well provided in nutrients but optimum on good soils. Native to Europe, West Asia and North Africa. Has become subcosmopolitan in temperate area to mostly. From the lowlands to alpine levels in mountain areas. |