*1: Perranporth sand
dunes, 1922, FR (BM) (Paton 1969a:
727).
*2: Whitesand Bay, 1890, AL
(OXF) (Paton 1969a:
727).
Commonly grows as extensive cushions or larger low
patches, which tend to spread vegetatively to form extensive
lawns that exclude other bryophytes. Evidently, therefore,
long-persistent at many of its sites.
Habitat notes from C&S are as follows. A
calciphile that is commonest in Cornwall on calcareous sand
in very short grassland on stable sand-dunes. Also occurs in
coastal sites where blown sand forms deposits on coastal
hillslopes (once over slope of old copper mine spoil), and
more locally on soil of sea-cliff ledges and slopes, in old
quarries near coasts and open areas in coastal heaths.
Scattered also inland and on coast on old calcareous masonry
(mortared stonework, concrete; on rather dry to damp, and
vertical to horizontal surfaces), e.g. tops and sides of old
walls, bridge parapets, beside churches, on graves, and ruins
including those of disused china-clay works. Also recorded
beside estuaries on slaty rocks and thin overlying soil in a
cutting and on a quarried cliff, on steep damp gabbro rock on
heathy slope above sea-cliff, and on gravel of a disused
railway. Normally grows unshaded, or only lightly shaded; once
seen on old wall moderately shaded by deciduous
trees.
On stable sand dunes and sandy coastal slopes it
often forms extensive pure patches, or occurs with Barbula convoluta, Bryum cf. algovicum, Didymodon vinealis, Ditrichum gracile, Homalothecium
lutescens, Hypnum
cupressiforme var.
lacunosum, Tortella
flavovirens, Trichostomum
brachydontium, Aphanes sp., Cerastium sp., Festuca rubra, Holcus lanatus, Plantago coronopus, Senecio jacobaea
(seedlings), Thymus
polytrichus; less commonly with Amblystegium serpens
var. salinum,
Brachythecium
glareosum, Didymodon acutus, Pleurochaete
squarrosa. Associates recorded on masonry are Tortella nitida, Tortula muralis. On
slate/shale cliff with Bryum capillare, Weissia brachycarpa
var. obliqua,
Conocephalum
conicum.
Occasionally c.fr. (ten records): capsules immature
1, 4; dehisced [4 old], 5, 7.
