Scirpus Maritimus Swamp Scirpetum Maritimi (Br.-Bl. 1931) R.Tx. 1937

Synonymy Scirpus maritimus zone Willis & Davies 1960; Stands dominated by Scirpus maritimus Gimingham 1964; Scirpetum maritimi Packham & Liddle 1970; Brackish water communities Birks 1973 p.p.; Scirpus maritimus nodum Adam 1976. Constant species Scirpus maritimus. Rare species Juncus subulatus. Physiognomy The Scirpetum maritimi is always dominated by Scirpus maritimus which usually forms a tall dense cover, about 60-80 cm high in which up to 10 shoots dm -2 have been recorded (Gimingham 1964tz). No other species is frequent throughout. Pure stands are common and very rarely are there more than ten associates. Most often, there are scattered plants of a wide range of species characteristic of the upper salt-marsh and strandline: Triglochin maritima, Juncus gerardi, Oenanthe lachenalii, Cochlearia anglica, Plantago maritima, Elymus pycnanthus and Apium graveolens are those most commonly encountered. Even in the richer sub-communities, which are distinguished by the constancy of additional species, the associates rarely exceed a combined cover of 30% and most frequently form a patchy cover beneath the canopy of S. maritimus. S. lacustris ssp. tabernaemontani is rare here and never abundant. Bryophytes are very sparse but there may be a prominent mat of algae over the substrate surface and around the bases of the Scirpus stools. Gimingham (1964a) noted the abundance of Vaucheria spp. in this algal mat in Scottish stands of the community. The Mediterranean maritime rush, Juncus subulatus, has become naturalised within the Scirpetum maritimi on the young salt-marsh at Berrow in Somerset (Willis & Davies 1960). It successfully competes against S . maritimus there by healthy rhizome extension. Sub-communities Sub-community dominated by Scirpus maritimus. In the very species-poor vegetation of this sub-community, S. maritimus occurs alone or with one or two associates of salt-marsh communities and freshwater swamps. Surface algae, Ruppia maritima or tall swamp species such as Phragmites australis or Glyceria maxima occasionally attain local prominence. Atriplexprostrata sub-community: Halo-Scirpetum maritimi (van Langendonck 1931) Dahl & Hadac 1941. Here, Atriplexprostrata is constant and forms, with the less frequent Puccinellia maritima, rayed Aster tripolium, Triglochin maritima and a variety of upper-marsh species, an open ground cover.