NVC community CG4 is one of the calcicolous grassland

Calcicolous grasslands in the British National Vegetation Classification system

This article gives an overview of the calcicolous grassland communities in the British National Vegetation Classification system.-Introduction:The calcicolous grassland communities of the NVC were described in Volume 3 of British Plant Communities, first published in 1992, along with the...

 communities in the British National Vegetation Classification

British National Vegetation Classification

The British National Vegetation Classification or NVC is a system of classifying natural habitat types in Great Britain according to the vegetation they contain....

 system. It is one of four communities of rank, tussocky grassland associated with low levels of grazing, within the lowland calcicolous grassland group.

It is a comparatively widely distributed community. There are three subcommunities.

Community composition

The following constant species are found in this community:

• Tor-grass
  Tor-grass
  Tor-grass is a plant in the grass family, with a widespread distribution in temperate regions of the Northern Hemisphere. It typically grows in calcareous grassland, and reaches 70–120 cm tall. The flowerhead is open, with 10 to 15 erect spikelets.The caterpillars of some Lepidoptera use it...
  
   (Brachypodium pinnatum)
• Glaucous Sedge (Carex flacca)
• Sheep's Fescue
  Sheep's Fescue
  Sheep's Fescue or Sheep Fescue is a species of grass.-General Description:It is a perennial plant sometimes found in acidic ground, for example in the Portlethen Moss, Scotland and mountain pasture, throughout Europe and eastwards across much of Asia; it has also been introduced to North...
  
   (Festuca ovina)

The following rare species are also associated with the community:

• Purple Milk-vetch (Astragalus danicus)
• Musk Orchid
  Musk Orchid
  The musk orchid is a commonly occurring species of European orchid.-Status in Britain:Musk orchids have a localised distribution in Britain. Sites where it is found include Ham Hill in Wiltshire....
  
   (Herminium monorchis)

Subcommunities

There are three subcommunities:

• the so-called typical subcommunity:
• the Avenula pratensis - Thymus praecox subcommunity
• the Centaurea nigra - Leontodon hispidus subcommunity
• the Holcus lanatus subcommunity