Range & Status
Known in W. Europe from S. Ireland and Wales eastwards to Sweden, Bulgaria and Italy; also in N. America. In Britain known only in N. Wales (two 10km squares + five pre-1950) and Cornwall. C. massalongi is a member of a rather critical genus of very small leafy liverworts; it was not generally distinguished from C. nicholsonii until after the study by Paton (1984).
Scattered modern records from total of ca. 30 sites, all on old copper mining ground.
Habitat & Ecology
Confined to acidic substrates with copper contamination, on mine-spoil, in crevices of walls and on banks. Some of its Cornish sites are wet, for example on a flushed stream bank, the others are at least humid, as for example on partly shaded north-facing slopes. The species is reported to be autoicous, but possibly also dioicous. However, in Britain female inflorescences are rare and male inflorescences and sporophytes are unknown. Foliar gemmae are common.
At risk mainly from landscaping and other ' tidying' on areas of old copper-contaminated mine-spoil. Some populations could be threatened by capping of old mine-shafts or development on old mine sites. Several populations have been lost due to shading as scrub and saplings surround its habitats.
Several Cornish sites are on protected land in SSSI. Treated as Vulnerable in Red-list (Church et al ., 2001).