The descriptive text, below the map, is from the Cornish Red Data Book (2009). The map on this web page depicts the organisms distribution and shows the records made pre-2000 and those made since.
Range & Status
Apparently endemic in NW. Europe, where known only in England, France and Norway. Britiish localities are only in Cornwall, S. Devon and Cheshire. However, it is likely to be under-recorded because good fertile material is needed for identification and capsules are rather rarely produced.
Recorded from oligotrophic streams in scattered localities (SW42, SW43, SW73, SX17, SX26), but probably under-recorded (see above).
Habitat & Ecology
Grows submerged on stones in soft-water streams, often in sites shaded by trees as well as in open places. It is only identifiable with capsules which are (at most) of infrequent occurrence and mature from March to June.
Susceptible to pollution of the streams in which it grows, and especially at risk from nutrient enrichment such as could occur from sewage or run-off of nitrates from agriculture.
None, although some of the rivers in which it occurs are monitored and managed by the Environment Agency. A substantial proportion of all known localities for this moss are in Cornwall, suggesting our populations may be of international significance. Consequently, the bio-systematic status of var. curnowii deserves further study, as does its Cornish distribution.
I.J. Bennallick, S. Board, C.N. French, P.A. Gainey, C. Neil, R. Parslow, A. Spalding and P.E. Tompsett. eds. 2009. Red Data Book for Cornwall and the Isles of Scilly. 2nd Edition.Croceago Press.
The Cornish Red Data Book Project was led by the Cornwall and Isles of Scilly Federation for Biological Recorders (CISFBR). The full text and species accounts (minus the maps) are available on the CISFBR website.