Sparganium erectum Branched Bur-reed

A large, upright, bur-reed with robust, shoots, strongly keeled (triangular), stiff aerial leaves (10-30mm wide) and branched inflorescences which bear numerous male and female heads. It is a rhizomatous perennial which grows in the emergent margins of slow-flowing water bodies such as ponds, lakes and canals and also in fens and unlike the other British bur-reeds it rarely has floating leaves. While it is often found in mesotrophic water it will also tolerate eutrophication. Flowers are wind pollinated and the fruits are dispersed in water. It is common everywhere in Britain except for the Scottish Highlands and is found throughout Wales. In West Glamorgan it has a largely lowland distribution in freshwater habitats in Gower, Swansea and Neath Port Talbot, and is particularly frequent in the canals of the Neath and upper Tawe valleys and also in swampy or fen-like habitats. It seems to be uncommon in the Afan Valley.

Native

Sparganium erectum is split into four subspecies by Stace (2019), who provides a short key to them. Others regard Sparganium erectum as an aggregate of species. They are distinguished by the morphology of their fruit.