Synonymy

Sagittario-Sparganietum emersi R.Tx. 1937 p.p.

Constant species

Sagittaria sagittifolia.

Rare species

Spirodela polyrhiza.

Physiognomy

This community comprises stands which have Sagittaria sagittifolia as the dominant emergent. Other species are only occasional and the most frequent are various duckweeds. Submerged aquatics such as Hydrocharis morsus-ranae or Sparganium emersum and other swamp dominants such as Glyceria maxima and Sparganium erectum may be locally abundant.

Habitat

S. sagittifolia is most characteristic of moderately deep eutrophic waters and soft silty substrates in wide dykes, canals and high-order streams. Although typical of standing or slow-moving waters, the early, submerged strap-shaped leaves are quite resistant to turbulence. Some non-eutrophic pollutants damage the species (Haslam 1978).

Zonation and succession

The community seems to be most frequently encountered as a fringe to other swamp communities such as the Scirpetum lacustris, Glycerietum maximae and Sparganietum erecti.

Distribution

Stands of S. sagittifolia have a scattered occurrence through the central and southern lowlands of England but the susceptibility to pollution may have reduced its distribution in recent years.

Affinities

The community is similar to 5. sagittifolia vegetation described from Germany (Tüxen 1937) and The Netherlands (Westhoff & den Held 1969).