An annual of periodically wet or inundated acidic to neutral soils on gravelly tracks, pool and ditch margins, in very short heathy swards and grassland; also recorded on clinker in railway sidings. Lowland.
This species was not recorded in Hampshire until 1920 and it appears to have spread steadily in the New Forest since 1950. Cornish populations remain fairly stable, with most losses there having occurred before 1930. Old records from the Outer Hebrides have not been confirmed but subfossil pollen has recently been discovered there, suggesting that they may be correct (Whittington & Edwards, 2000).
Suboceanic Southern-temperate element.
Light (Ellenberg): 8
Moisture (Ellenberg): 7
Reaction (Ellenberg): 3
Nitrogen (Ellenberg): 2
Salt Tolerance (Ellenberg): 0
January Mean Temperature (Celsius): 5.6
July Mean Temperature (Celsius): 15.7
Annual Precipitation (mm): 1062
Height (cm): 20
Perennation - primary
Life Form - primary
Clonality - primary
Clonality - secondary
Count of 10km squares in Great Britain: 37
Count of 10km squares in Ireland: 0
Count of 10km squares in the Channel Isles: 0
Atlas Change Index: -0.6
Scarce Atlas Account
Illecebrum verticillatum L.
I. verticillatum is an annual plant of neutral to acid soils, found in seasonally wet sandy or gravelly tracks. In the New Forest it occurs in very short heathy swards, heavily grazed lawns' near settlements, winter-wet hollows in tracks and at the edges of pools in the `tide-mark' left when water levels drop. It is found in similar sites in Cornwall, but the largest Cornish populations are on the shallower edges of streams and the flooded ditches that branch off from them. Associates in tracks are Gnaphalium uliginosum, Radiola linoides and the scarce Cicendia filiformis. Around New Forest pools other species include Galium constrictum, Hydrocotyle vulgaris, Littorella uniflora with, at times, Anagallis minima and Cicendia filiformis. In Cornish streams, the main associates are Eleogiton fluitans, Juncus articulatus, Lythrum portula and Potamogeton polygonifolius.
The main flowering period is July to September, self-pollination being followed by the development of one-seeded fruits. Where the plant is growing in streams and pools it is noticeable that flowering takes place only on emergent stems. Seed germination can be held back by cold dry springs. In Cornwall the range of flowering time is more variable, and flowers have been found as early as June and as late as December.
This species is holding its own in the New Forest. It has, however, shown a marked decline in Cornwall where it has been recorded in only 10 of its 57 tetrads since 1987 and is now confined to strongholds in West Penwith, Goss Moor and Bodmin Moor. Outside its native range plants have become established on the moist gravels and clinker of disused railway lines. One population has been found in a disused china-clay pit.
This is a western European species, widespread from Spain to Germany and Poland and with a few scattered sites in the Mediterranean region (Jalas & Suominen 1983). It also occurs in the Azores and the Canaries.
R. J. Murphy
Atlas text references
1996. The flora of Hampshire.
1986. Atlas of north European vascular plants north of the Tropic of Cancer. 3 vols.
Jalas & Suominen (1983)
1965. Vergleichende Chorologie der zentraleuropäischen Flora. Volume 1. 2 vols.
1994. Scarce plants in Britain.