*1: Newlyn Cliff, 1861,
WC (PNZ) (Paton 1969a: 729).
*2: Near Trehane, W. of
Probus, 1861, ES (TRU) (Paton 1969a:
729).
Recorded as 'var. pulvinata' frequently
when the operculum was checked. A few capsules seen were only
rostellate rather than rostrate but no material clearly
referable to 'var. africana' has been
seen.
Forms neat cushions which may extend or coalesce to
create larger patches. Habitat notes from C&S are as
follows. A basiphile of hard dry masonry or rocks, often
growing on firm open surfaces or in crevices and on small
ledges, on horizontal, inclined or vertical aspects, typically
in unshaded or lightly shaded sites (sometimes moderately
shaded beneath trees). Commonest on calcareous man-made
substrates (mortar and adjacent stonework or bricks, old and
modern concrete, asbestos-cement sheets; once on old tarmac)
such as on walls, ruined walls, fragments of old masonry,
gravestones and grave surrounds, and varied structures
including bridges, modern reservoir dams, ruins of old
mine-building, concrete fence-post tops and church walls. On
natural rock, frequent only on blocks, boulders and outcrops
of serpentinite. Occasionally also on blocks and boulders of
gabbro, granitic rocks (in open and e.g. in 'hedges') and
slaty rocks (at exposures above sea-cliffs, in 'hedges', and
in old quarries and road-cuttings), especially on coasts where
salt-spray or blown sand presumably supply extra bases, but
sometimes far inland where presumably it is on rocks with
higher than usual base-content. Common associates are Bryum radiculosum, Didymodon luridus, Didymodon rigidulus,
Orthotrichum
anomalum, Schistidium apocarpum,
Schistidium
crassipilum, Tortula muralis, Zygodon viridissimus
var. viridissimus,
scarcer ones include Bryum dichotomum, Syntrichia laevipila,
Tortula atrovirens,
Tortula cuneifolia.
The usually more acidophilous Grimmia lisae often
occurs with G. pulvinata on
serpentinite and slate cliffs and both that species (e.g. at
Sennen Cove) and Grimmia trichophylla
occasionally occur with or near it on granitic rocks and masonry. G. pulvinata is
evidently a good colonist, presumably from wind-blown spores,
to judge from records on isolated habitats such as concrete
gate-posts or a small concrete block isolated amongst acidic
mine-spoil.
Commonly cfr; capsules immature 1-5 (6, 7), 10-12;
dehiscing 3-7 [8]; dehisced [old 1-5],
5-12.