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Blister Sedge

Blister Sedge

Carex vesicaria

Identify the Blister Sedge from a photo and log your finds with Florapass.

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How common: Common

Blister Sedge is a tall, grass‑like wetland plant that forms loose tufts and wide patches. You’ll see it along lakeshores, riverbanks, flood meadows, streams, pools and ditches. In summer the lower flower clusters develop pale, swollen seed cases that look like tiny blisters.

Did you know?

  • The “blister” name comes from the inflated seed cases that look like tiny balloons.
  • Roll the stem between your fingers: the three sharp edges are easy to feel.

About the species

Identification

Upright, grass‑like plant 30–90 cm tall, forming loose tussocks and spreading patches. Stems feel sharply three‑edged and rough near the top. Leaves are narrow (4–8 mm), flat, yellow‑green and about as long as the stem; the leaf bases are often reddish brown and fibrous. Flower clusters are stacked: 2–4 slender pollen clusters at the top, with 2–3 shorter, denser seed clusters below. Later these lower clusters carry many pale, swollen, egg‑shaped cases (5–8 mm) each with a long, deeply notched tip. These “blisters” droop with age. Compared with Bottle Sedge, the cases are plumper and less long‑beaked. Flowers in Finland in June–July.

Plant group

Grasses, sedges and rushes

Habitat

shore

Flowering

Jun–Jul

About the habitat

Grows on the edges of lakes and rivers, on flood meadows, along streams, in pools, ditches and wet fens; often forming wide stands in muddy or peaty ground. Common almost throughout the country; rather scarce in northernmost Lapland.

Sources

Photo: Franz Xaver, CC BY-SA 3.0 https://commons.wikimedia.org/wiki/File:Carex vesicaria 1.jpg

Text: Pinkka: BIO-503 Suomen kasvisto ja kasvillisuus - Sisävedet: rantaniityt, CC BY 4.0 https://laji.fi/taxon/MX.40345

Text: Pinkka (Luomus), CC BY 4.0 https://laji.fi/taxon/MX.40345

Text: Pinkka: Kasvitieteen retkeily Ahvenanmaalle - Nåtön luontopolku, CC BY 4.0 https://laji.fi/taxon/MX.40345

Text: Wikipedia (Finnish), CC BY-SA 4.0 https://fi.wikipedia.org/wiki/Luhtasara

See also