Branched Bur Reed

Branched bur-reed is a perennial species that flowers from June to August (1). The leaves arise from rhizomes and die back at the end of each year (4). Although insects do visit the flowers, they are only attracted to male flowers, and so pollination by insects is not important. Pollination is mainly by wind, although self-fertilisation may occur. The fruits can float for a number of months, which aids in their dispersal. They germinate under water, but seedling survival is poor. The plants can also spread (by vegetative reproduction) from the rhizomes (6).

Conservation action is not required for this common species.

Branched bur-reed is an aquatic emergent plant that grows rooted in the mud at the margins of waterbodies (4). The narrow, smooth and keeled leaves are erect and triangular in cross-section (2). The globular flowers are produced on a branching spike hence the name 'branched' bur-reed. Flowers at the tip of the spike are male whereas those further down are female (4). The female flowers take on a bur-like appearance before breaking up into distinct fruits (5). The fruits are small, dry and spongy and contain 1-2 seeds (4).

Typically found growing in a narrow band at the margins of lakes, rivers, streams, ditches and canals. Occasionally, large clumps of branched bur-reed may occur in swampy habitats. Cattle graze on this species, and so it is unusual to find branched bur-reed on banks where livestock graze (3).

This native bur-reed is widespread throughout Britain, reaching altitudes of 425 m (3). It is absent from Shetland (2). It is also found in most northern temperate areas of the world (2), but is absent from eastern North America (3).

Common and widespread: not threatened (3).

This species is not threatened.

Foodplant / feeds on
Bagous lutosus feeds on Sparganium erectum
Other: sole host/prey

Foodplant / feeds on
larva of Donacia aquatica feeds on root of Sparganium erectum

Foodplant / open feeder
adult of Donacia bicolora grazes on leaf of Sparganium erectum
Remarks: season: 4-early 8(-11)

Plant / resting place / among
cocoon of Donacia cinerea may be found among roots of Sparganium erectum
Other: minor host/prey

Foodplant / feeds on
adult of Donacia marginata feeds on pollen? of Sparganium erectum
Remarks: season: (4-)6-8(-10)

Plant / associate
cocoon of Donacia semicuprea is associated with Sparganium erectum

Plant / resting place / among
cocoon of Donacia simplex may be found among root of Sparganium erectum

Plant / resting place / on
adult of Donacia sparganii may be found on leaf of Sparganium erectum

In Great Britain and/or Ireland:
Foodplant / feeds on
Erirhinus aethiops feeds on stem of Sparganium erectum

Plant / resting place / among
subaquatic cocoon of Macroplea appendiculata may be found among roots of Sparganium erectum

Plant / resting place / among
cocoon of Plateumaris sericea may be found among root of Sparganium erectum

Foodplant / saprobe
often numerous, immersed, black pycnidium of Stagonospora coelomycetous anamorph of Stagonospora typhoidearum is saprobic on sometimes locally discoloured leaf of Sparganium erectum

Foodplant / feeds on
larva of Telmatophilus brevicollis feeds on Sparganium erectum

Foodplant / feeds on
larva of Telmatophilus caricis feeds on Sparganium erectum

Foodplant / feeds on
larva of Telmatophilus sparganii feeds on Sparganium erectum

Foodplant / internal feeder
larva of Thryogenes scirrhosus feeds within stem? of Sparganium erectum
Other: major host/prey

Sparganium erectum, the simplestem bur-reed or branched bur-reed, is a perennial plant species in the genus Sparganium.

The larvae of the moth Plusia festucae feed on Sparganium erectum.

Fruits

Subspecies:

Sparganium erectum subsp. microcarpum (Neuman) Domin (synonym: Sparganium microcarpum (Neuman) Celak.)