British NVC community OV41 (Parietaria diffusa community) is one of the open habitat

Vegetation of open habitats in the British National Vegetation Classification system

This article gives an overview of the plant communities formed by vegetation of open habitats in the British National Vegetation Classification system.-Introduction:...

 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 six communities of crevice, scree and spoil vegetation.

This community is widely distributed in suitable habitats in the southern lowlands of Britain.

There are two subcommunities.

Community composition

One constant species is found in this community:

• Pellitory-of-the-wall (Parietaria judaica
  Parietaria judaica
  Parietaria judaica, common name Spreading Pellitory or Pellitory of the wall, is a species of herbaceous perennial plant in the family Urticaceae, commonly nicknamed sticky-weed. The plant's pollen is highly allergenic. In Australia it is also known as asthma weed, due to the high incidence of...
  
  )

Three rare species are associated with the community:

• Wild cabbage (Brassica oleracea
  Brassica oleracea
  Brassica oleracea, or wild cabbage, is a species of Brassica native to coastal southern and western Europe, where its tolerance of salt and lime and its intolerance of competition from other plants typically restrict its natural occurrence to limestone sea cliffs, like the chalk cliffs on both...
  
  )
• Yellow whitlowgrass (Draba aizoides
  Draba aizoides
  Draba aizoides is a species of Draba, known as yellow whitlow-grass.-Description:Draba aizoides is a perennial plant, with a basal rosette of linear, entire leaves...
  
  )
• Nottingham catchfly (Silene nutans)

Distribution

This community is widely distributed in suitable habitats in the southern lowlands of Britain, mainly in south-east England. It is found on sunny ledges and in crevices on limestone quarry rock faces and cliffs and mortared walls; the Daucus carota subcommunity, which is restricted to coastal locations, is found as far west as south Wales.

It is essentially the same as the Parietarietum judaicae assemblage recognised in other parts of Europe.

Subcommunities

There are two subcommunities:

• the Homalothecium sericeum - Tortula muralis subcommunity
• the Daucus carota subcommunity