Alopecurus geniculatus L.
Author: Alain Peeters
Marsh foxtail or floating foxtail (English), Vulpin genouillé (French), Knick-fuchsschwanz (German).
Annual or perennial plant, small size, hairless (except spikelets), stoloniferous. Stems first creeping, rooted on the node, then raised (ascendent stolons), 15 - 60 cm high. Blade rolled when young, rather short, wide (3 - 5 mm), with clear veins, green to greyish green. Sheath of the upper leaf a little bulging. Ligule long. No auricles. Spike-like inflorescence, much shorter and thinner than A. pratensis, hairy-silky, dark green to black. Spikelets 1-flowered. Glumes just united at the basis, lengthily ciliate on the back. Lemma awned. Chromosome number: 2n = 28.
Large distribution in temperate climates. Cold resistant.
On wet to very wet soils often in small dips or in hollows of micro-reliefs (wheel tracks of tractor). Moderately demanding (mesotrophic) to very demanding (eutrophic) from the point of view of the soil nutrient availability. Thus, distinguishable from the ecology of Agrostis canina which has the same preferences for soil humidity but at a much lower nutrient availability level. Often on clay or peat soils, rich in nutrients.
Native to Europe and Western Asia.