Deschampsia setacea

Tracheophyta MagnoliopsidaPoaceaeDeschampsiaDeschampsia setacea


A densely tufted perennial of peaty or stony margins of lochs, shallow pools and seasonally inundated depressions on heaths, and on acid bogs. It appears to favour bare areas that are flooded in winter but dry in summer, and possibly where there is some lateral water movement. 0-320 m (Loch Morlich, Easterness).



World Distribution

Oceanic Temperate element.

Broad Habitats

Light (Ellenberg): 8

Moisture (Ellenberg): 9

Reaction (Ellenberg): 2

Nitrogen (Ellenberg): 1


Salt Tolerance (Ellenberg): 0

January Mean Temperature (Celsius): 3.5

July Mean Temperature (Celsius): 13.6

Annual Precipitation (mm): 1211

Life form information

Height (cm): 70

Perennation - primary


Life Form - primary




Clonality - primary

Tussock-forming graminoid, may slowly spread

Count of 10km squares in Great Britain: 125

Count of 10km squares in Ireland: 11

Count of 10km squares in the Channel Isles: 0

Atlas Change Index: -0.04

Distribution information

JNCC Designations


External Species Accounts

Scarce Atlas Account

Scarce Atlas Account: 

Deschampsia setacea (Hudson) Hackel

Bog hair-grass

Status: scarce


A grass of the bare, sometimes stony, margins of shallow pools; of seasonally inundated depressions on heaths, with Molinia caerulea, Eleocharis multicaulis and species of algae; and of acid bogs principally on lowland heaths. In the south of England it grows in wetter areas than Agrostis curtisii, which can look very similar. Winter inundation seems to be a requirement (Baker 1866), as does drying out in summer (Hughes 1983), and it may also be necessary that this water is moving, no matter how slightly. It will not grow on dry ground. D. setacea prefers an open situation, and can gradually be crowded out by more aggressive plants. It fares better where bare soil is present in quadrats than where many species are recorded (Hughes 1984), Molinia caerulea is a constant associate. The majority of sites in Britain are lowland and coastal, but it is found up to 320 metres, by Loch Morlich. 

It is a densely tufted perennial with many vegetative shoots. It presumably spreads by seed, but little is known of its reproductive method, nor why the plant is in such small quantity at most of its stations. It is occasionally viviparous.

There are now more records from north and northwest Scotland than were known to Perring & Walters (1962), purely because of increased recording, and the species may still be at many of its sites in the Outer Hebrides for which only pre-1970 records are available. Further south, there are few recent records, and the rank state of many heaths may be responsible for this, However, it is difficult to see in flower, and very elusive indeed in its vegetative state (Lousley 1976).

D. setacea is an oceanic species which is endemic to western Europe, from Norway and Poland southwards to Spain. It is threatened by habitat destruction in much of its European range.


D. A. Pearman

PLANTATT - Attributes of British and Irish plants. (.zip 1455KB) This dataset was compiled and published in 2004, and last updated in November 2008. Download includes an Excel spreadsheet of the attributes, and a PDF explaining the background and nomenclature. Note that the PDF version is the booklet as published, whereas the Excel spreadsheet incorporates subsequent corrections. A hardcopy can be purchased from the Centre for Ecology and Hydrology.