British NVC community MG4

British NVC community MG4 ("Alopecurus pratensis - Sanguisorba officinalis" grassland) is one of the mesotrophic grassland communities in the British National Vegetation Classification system. It is one of four such communities associated with well-drained permanent pastures and meadows.
This community, although widespread in the past, now has a scattered distribution in the Midlands and southern England. One rare species rare species is associated with this community: snake's-head fritillary ("Fritillaria meleagris") and six rare micro-species of dandelion, "Taraxacum fulgidum", "T. haematicum", "T. melanthoides", "T. sublaeticolor", "T. subundulatum" and "T. tamesense".
There are four subcommunities.
Subcommunities.
The Cock’s-foot sub-community is the most species-rich of the four sub-communities and is generally found where the water table remains low throughout the growing season and flooding is rare. Distinguishing species that are constant include cock’s-foot ("Dactylis glomerata") and yellow oat-grass ("Trisetum flavescens"). Meadow foxtail, ("Alopecurus pratensis") which is included in the scientific name for the overall community is found only sparsely and patchily in this sub-community.
The Typical sub-community, as its name implies, describes those stands closest in their species composition to the Burnet floodplain meadow community as a whole. However, stands of the Typical sub-community are less species-rich than those of the Cock’s foot sub-community, with on average 22 species per square metre, and there are no strongly preferential species
The Yorkshire fog sub-community has a high cover of grasses such as meadow foxtail ("Alopecurus pratensis"), rough-stalked meadow-grass ("Poa trivialis") and creeping bent ("Agrostis stolonifera"). It tends to be associated with sites which experience a high water table for longer periods during the growing season than the two preceding sub-communities. It is less species-rich than the Cock’s-foot and Typical sub-communities.
The Creeping bent sub-community is the most species-poor. It tends to be associated with areas that experience prolonged inundation (which can also lead to higher soil fertility) and is especially characteristic of the Derwent Ings in Yorkshire. 
Community composition.
The following constant species are found in this community: