Synonymy

Agropyretum pungentis Perraton 1953; includes Agropyron pungens-Juncus maritimus nodum Adam 1976.

Constant species

Elymus pycnanthus.

Physiognomy

The association is invariably dominated by the stiff clumps of Elymus pycnanthus and this may be the sole species. Usually, however, there are a few associates though these are somewhat varied and individual stands may be rendered distinctive by the abundance of (a) particular species. Sometimes there is a patchy or extensive understorey of Halimione portulacoides, Artemisia maritima and/or Puccinellia maritima. In other cases, Atriplex prostrata and/or Festuca rubra may be conspicuous. Juncus maritimus is sometimes abundant though stands with this species are not worthy of distinction as a subcommunity (cf. Adam 1976, 1977). Other stands have a prominent umbelliferous element with Conium maculatum, Foeniculum vulgare and Smyrnium olusatrum and, more locally, Petroselinum segetum and Sison amomum.

Habitat

The Atriplici-Elymetum is an upper-marsh community occurring on a variety of substrates including organicallyenriched clay, sand (where Festuca rubra is often abundant) and shingle. Substrates are generally well-drained and there is often considerable free calcium carbonate derived from inwashed shell fragments. The pH is generally above 7.0. The association also occurs on older, partly decayed drift litter, where Atriplex prostrata flourishes, but in many stands there is little litter except at the seaward edge.

The association may be confined to a narrow strip around the tidal limit or form extensive stands in the upper marsh; occasionally it forms mosaics with other communities.