Taxonomy

Nice and simple: Carex vesicaria L., Bladder Sedge, has no synonyms. The American name for it seems to be Blister Sedge.

2n = 74.

Identification

The biggest problem is distinguishing it from Bottle Sedge C. rostrata. They are quite similar in height and fruiting spikes; they grow in similar habitat; and they both forms extensive, rhizomatous, swamps. Sometimes they even grow together.

Differences include:-

Distribution

Widespread throughout the British Isles, but absent from the Northern Isles and very rare in the Outer Hebrides.

GBIF shows it as frequent throughout Europe and North America with scattered localities in other parts of the world.

Status

Origin: native throughout the British Isles. The first British record is given as 1699 in Clarke (1900).

Rarity: common and widespread.

Threat: in the New Atlas it is given a Change Index of -0.52, which is quite a severe decline. Cheffings & Farrell (2005) list it as Least Concern.

Conservation: for such a widespread plant, C. vesicaria is usually popular with county recorders, as most list it as an axiophyte. It is a useful indicator of swamps, wet meadows and some of the more base-rich mires.

Ecology

The most obvious vegetation community is S11 C. vesicaria swamp, but it is easy to make the mistake of thinking that all stands of C. vesicaria are this community.

Rodwell (1991-200) also allows it as a constituent OV30, S27, M27.

It grows in places where there is a high water table, possibly fluctuating slightly, but rarely completely inundated. Substrates include mineral soils and peat, but it does not grow on ombrotrophic mires. Its light requirement is high (Ellenberg L value of 8, according to Hill et al., 1999), but it would presumably only tolerate light grazing.

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