Synonymy

Litter Godwin & Tansley 1929; Molinietum Godwin 1941, Willis & Jefferies 1959, Ivimey-Cook et al. 1975 p.p.; Molinia-edge Haslam 1965; Cirsio-Molinietum peucedanetosum (Sissingh & De Vries 1942) Wheeler 1978; Cirsio-Molinietum (Sissingh & De Vries 1942) Wheeler 1980c p.p.; Grassy Heath NCC Devon Heathland Report 1980.

Constant species

Carex panicea, Cirsium dissectum, Lotus uliginosus, Molinia caerulea, Potentilla erecta.

Rare species

Hypericum undulatum, Peucedanum palustre, Selinum carvifolia.

Physiognomy

The Cirsio-Molinietum caeruleae includes the bulk of the Molinia caerulea vegetation in the lowland south-east of Britain. Molinia is almost always the dominant plant in the community and it can be very abundant, forming the basis of a rough sward or occurring as a more stronglytussocky cover, a kind of structure well shown in the classic early account of this vegetation from Wicken Fen in Cambridgeshire (Godwin & Tansley 1929). And there are stands in which the abundance of Molinia is so overwhelming that its dense herbage and thick litter reduce the associated flora to scattered individuals of a very few species. Often, however, the number of companions is considerable: although many of the associates are plants of fairly wide distribution among damper meadows and pastures, the most frequent of them comprise a quite distinctive assemblage, and some of the preferentials attain such local prominence as to mask the major contribution which Molinia and the other constants make to the community. Much of this character reflects the origin of this kind of vegetation from rather diverse precursors by the application of particular treatments.

In structural terms, the most important associates of Molinia are other monocotyledons of medium stature, particularly rushes, which can make quite a substantial contribution to the dense layer of herbage characteristic of the community. Typically, this is 20-60 cm tall, though its physiognomy is strongly dependent on the style and incidence of treatment: in grazed stands, for example, the cover can be shorter than this, with stretches of close-cropped sward running among clumps of more resistant plants; where there is no grazing, and where the vegetation has not been mown for some time, the herbage can be taller and ranker. The trophic state of the substrate also influences the structure of the vegetation, with shorter and more open swards developing over more calcareous and impoverished soils.