Synonymy

Rhodioletum roseae Nordhagen 1922 p.p.

Constant species

Festuca rubra, Armeria maritima, Rhodiola rosea, Rumex acetosa.

Physiognomy

The luxuriant herbaceous vegetation of this community has no single dominant. Usually, robust plants of Rhodiola rosea and Rumex acetosa and large cushions of Armeria maritima grow from a matrix of Festuca rubra in irregular and often fragmentary stands on cliff ledges. Plantago maritima, P. lanceolata and Holcus lanatus are frequent, the last sometimes occurring in abundance. Tall herbs such as Angelica sylvestris and Silene dioica may be prominent. No bryophytes were recorded.

Habitat

The Rhodiola-Armeria community occurs on ledges, mostly north-facing, above the most maritime zone on sea-cliffs. It is found on a variety of rock types where suitable ledges are developed: particularly fine stands may occur on prominently-bedded rocks such as the Old Red Sandstone of Caithness. The soils are irrigated rankers. Stands are quite inaccessible to grazing animals.

Zonation and succession

Stands of the community are generally discrete but may form part of a fragmented zonation up cliffs from the Armeria-Ligusticum maritime rock-crevice community to a more intact Festuca-Armeria maritime grassland or maritime heath above. On very tall cliffs, there may be a transition to less maritime ledge vegetation such as that described by Birks (1973) from Skye as the Luzula sylvatica-Silene dioica Association.