An annual of moist, open disturbed ground around the margins of ponds and by ditches, often on ground subject to winter-flooding. The substrate may be peaty, muddy or stony but humus-rich. Seed may not be set in cool summers. Lowland.
The conditions favoured by C. fuscus were traditionally maintained by grazing animals, but cessation of grazing, encroachment by scrub and lowering of the water-tables have all contributed to an appreciable decline which began before 1930. However, current sites now benefit from statutory protection, and since seed appears to be long-lived, populations may be revived with suitable conservation management.
Eurosiberian Southern-temperate element.
Count of 10km squares in Great Britain: 11
Count of 10km squares in Ireland: 0
Count of 10km squares in the Channel Isles: 2
Atlas Change Index: -0.32
RDB Species Accounts
Cyperus fuscus L. (Cyperaceae)
Brown galingale, Ysnoden Fair Lwytgoch
Status in Britain: VULNERABLE. WCA Schedule 8.
Status in Europe: Not threatened.
C. fuscus is found on seasonally-flooded pond and ditch margins in southern England. Most of the populations grow on a peaty substrate or on sand and gravel rich in organic matter. The bulk of Britain's historic and extant colonies are associated with the Thames and Hampshire Avon (and tributaries), typically lying within the tertiary basin of these two rivers, often at the junction with the extensive southern chalk. Such sites are frequently commons with a long and continuous history of extensive grazing by livestock, which has maintained the open, poached conditions favoured by C. fuscus. Associates include Agrostis stolonifera, Bidens cernua, Gnaphalium uliginosum, Hottonia palustris, Juncus bufonius, Limosella aquatica, Mentha aquatica, Myosotis laxa, Persicaria hydropiper, P. minor, Ranunculus sceleratus and Rorippa palustris.
It is an annual, normally germinating in early summer, but at some sites germination has been recorded as late as August. Flowering is between July and September. Seed is presumably long-lived in the soil, since germination can be prolific following soil disturbance, even after years of apparent absence. In cultivation a relatively high temperature is required for germination (Tutin 1953), and plants may set little or no seed in a cool summer.
Always a rare plant in Britain, C. fuscus has only ever been recorded from twelve mainland localities, all in southern England, and one site in Jersey where it was refound in 1989. Today it is restricted to only six localities, in North Somerset, South Hampshire, Berkshire, Buckinghamshire and Surrey. Being an annual of seasonally-exposed pond margins, and often reliant on some form of disturbance, numbers are liable to fluctuate greatly from year to year. The two Hampshire colonies have consistently produced the largest number of plants in recent years, with the highest recorded population of over 36,500 plants at one site, whilst the North Somerset and Buckinghamshire colonies have consistently performed very poorly, with at best a handful of plants in the years in which it chooses to appear (Rich 1995e).
Most, perhaps all, of the extant colonies receive some form of protection, since they lie within SSSIs and/or nature reserves. In addition the plant is fully protected by law. Housing development, which destroyed its earliest known British colony in central London, does not pose a present threat to extant sites, but populations are threatened in other ways, principally from the cessation of grazing, invasion by willow and alder scrub, and the general lowering of the water table, particularly for sites in the Thames Basin. On a more optimistic note, the plant can respond vigorously to site clearance and the reinstatement of grazing. For instance, in Surrey 250 plants appeared at one site following clearance of willows.
C. fuscus is the most widespread of all the annual species of Cyperus, occurring throughout most of Europe, with its stronghold in the southern parts of the continent. There is one site in Jersey. It is absent from Iceland, the Faeroes, Ireland and Fennoscandia, and is rare or threatened in the Netherlands, Denmark and Switzerland. It is also found in Asia, North Africa, Madeira and Tenerife.
A. J. Byfield
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.