Range & Status
Mostly in S. and W. Europe, extending north to Wales and Luxembourg, east to Rhodes; also in Macaronesia and N. Africa. Known from only six sites in the British Isles: two in S. Devon, two in W. Ireland, one each in N. Wales and W. Cornwall.
The only Cornish site is near Penzance where it was discovered in 1868 and persisted in small quantity in 1993 despite past ravages of collectors. However, it was not refound by bryologists visiting the site more recently.
Habitat & Ecology
At the Cornish site it grows on firm, near-vertical soil of a stream bank, somewhat above flood-level and well shaded by trees. Elsewhere in Britain it is reported from a wider variety of habitats, including alluvial sand and gravel, rocks below flood-level of deeply shaded streams and wet shaded rocks in a cave (Smith in Hill et al ., 1992). It is a dioicous species, for which only male plants are known in Britain. Rhizoidal tubers have been reported on a specimen from Devon (Arts, 1988a).
Numerous herbarium specimens have been collected from the Cornish site in the past and collecting could still pose a threat. A survey of the site near Penzance is needed to establish its current status.
This species is listed on the UK BAP Priority Species list (2007).