THE BRYOPHYTES OF CORNWALL
AND THE ISLES OF SCILLY

*1: Soil exposed on margin of Stithians Reservoir, 1973, JAP (BBSUK) (Corley 1979: 22,  Paton MS.: 8), as R. warnstorfii. [Housel Bay, Lizard, 1916, WEN, of Nicholson 1917 was redetermined as R. crozalsii by Nicholson 1918; see Paton 1969a: 691].

*2: Damp clay on edge of pool, Retew near Fraddon [SW95], 1962, JAP (BBSUK) (Paton 1969a: 691, as R. warnstorfii). [Record published as R. warnstorfii from track, Rocky Valley, Tintagel, JAP & JA, in Paton 1961: 150, is based on R. crozalsii, fide Paton 1969a: 691].

British records were revised by Paton (1990b) who showed that older records of R. warnstorfii belong here. It is now one of the commonest Riccia spp. in Cornwall and occasional in Isles of Scilly. R. subbifurca may have increased in the past two decades (change index +127%) but it seems more likely to have been under-recorded in the past, presumably because it was often overlooked as Riccia glauca.

Habitat notes from C&S are as follows. On damp soil of old track through woodland, partly or slightly shaded (with Anthoceros punctatus, Phaeoceros laevis, Riccia glauca, Riccia sorocarpa). On compressed soil of bare areas on and beside paths on sea-cliffs and slopes above them (over granitic, slate and serpentinite rocks); unshaded; with Archidium alternifolium, Bryum dichotomum, Fossombronia 'husnotii', Pleuridium acuminatum, Riccia sorocarpa, Scleropodium touretii, Trichostomum brachydontium, Weissia spp., Sedum anglicum; rarely Weissia longifolia var. longifolia. On rather loose mainly bare soil of ant-hill on slope above sea-cliff, unshaded. On partly bare patches of soil in old serpentinite quarry above sea-cliff, in trampled places and on banks, unshaded. Compressed, partly bare soil on little-used path at edge of heathland near coast (over serpentinite), unshaded. Kynance Cliff: plentiful in patches/rosettes on damp partly bare soil of small hollow on top of serpentinite sea-cliffs (with Archidium alternifolium, Trichostomum brachydontium, locally Riccia beyrichiana); path on slaty sea-cliff slope. Bit on soil of bare areas in pastures and near edge of grass-ley (with Bryum rubens, bit Riccia sorocarpa). Damp soil at edge of cauliflower field, unshaded (with Dicranella staphylina, Riccia glauca, Tortula truncata). Soil in flax, fallow, daffodil (and other horticultural) and cereal stubble fields (near Barbula convoluta, Bryum rubens, Dicranella schreberiana, Dicranella staphylina, Trichodon cylindricus, Ephemerum minutissimum, Phaeoceros laevis, Riccia glauca, Riccia sorocarpa, Tortula truncata, rarely Anthoceros agrestis, Fossombronia wondraczekii, Riccia crozalsii; in Isles of Scilly with Riccia crystallina, Spherocarpos spp.). Soil in arable (fallow) field (near Dicranella staphylina, Trichodon cylindricus, Riccia sorocarpa, Tortula truncata). Colonist on bare recently disturbed soil in unshaded clayey hollow (with Phaeoceros laevis, Pleuridium subulatum). Soil exposed on stream bank. Partly bare soil of old cattle-trodden tracks, unshaded (with Trichodon cylindricus, Ephemerum serratum, Ephemerum sessile, Pseudephemerum nitidum, Riccia glauca, Riccia sorocarpa, Tortula truncata). Usually unshaded or lightly shaded, one record on thin soil over gabbro rock partly shaded by Grey Willow scrub on Lowland Point (with Bryum bornholmense, Bryum rubens, Ephemerum serratum s. l., Fossombronia 'husnotii', Riccia beyrichiana). Sparsely on unshaded mud exposed in inundation zones beside Argal and Stithians Reservoirs (with Bryum klinggraeffii, Dicranella staphylina, Leptobryum pyriforme, Riccia sorocarpa).

Spores mature: immature 9, mature 2, 3, 7, 9, recently dehisced 9.