*1: St Mary's, 1908,
GBS (RAMM) (Paton 1969a:
725).
*2: Helland Bridge, N.
of Bodmin, 1891, RVT (B) (Paton 1969a:
725).
Grows as low lawns or in smaller patches or tufts.
Notes on habitats in C&S are as follows. Commonest on
slightly acidic to basic soil, including thin soil over
masonry and in crevices; also on (mainly soft) calcareous
masonry, including concrete and damp vertical wall mortar.
Occupies sites that vary from rather damp to free-draining,
including dry duneland habitats alongside the scarcer D. vinealis and much
damper frequently inundated places with D. nicholsonii. Although
it most often grows fully insolated, it is also common in
moderately shaded places, including woodland banks and edges
where it is more tolerant of shade than most of our common
Pottiaceae. Often forms extensive patches on disturbed ground
such as soil heaps, in gardens and beside paths (frequent in
small amounts in arable fields, although not usually growing
to maturity there). Widespread on woodland, laneside, ditch or
stream banks, 'hedges', old tracks, track edges, lay-bys and
banks on old mining ground, in old quarries, on graves or on
walls; sometimes above sea-cliffs and locally on calcareous
sand in dune-grassland. Although less common growing directly
on firm masonry substrates than on soil it sometimes forms
substantial tufts on old partly shaded walls and even on
vertical surfaces of hard old concrete. D. insulanus occurs as a
colonist of soil and clay near working china-clay pits,
especially where masonry has been dumped, but it is also
locally abundant on open, disturbed lithosol substrates there.
Locally common also in open sites on old metalliferous mine
spoil. Occurs frequently on silted bases of trees in
flood-zone beside R. Tamar. An unusual record of it well
established with other mosses on decaying carpet lying on
mine-spoil (Tuckingmill). Also single record of patch on
vertical surface of old damp timber beside track in open
woodland. Associates commonly include Barbula convoluta, Barbula unguiculata,
Bryum dichotomum,
Ceratodon
purpureus, Kindbergia praelonga,
Fissidens
viridulus, Pseudocrossidium
hornschuchianum, more locally Anthoceros punctatus,
Didymodon
nicholsonii, Didymodon vinealis, Lophozia ventricosa,
Phaeoceros laevis
and many other small mosses and phanerogams. Associates on
shaded banks often include Kindbergia praelonga,
Fissidens bryoides
var. bryoides
and Fissidens
taxifolius var.
taxifolius. On bases of trees in flood zone of R. Tamar it
grows with Leskea
polycarpa.
Rhizoidal tubers recorded on material from a barley
stubble field, Feb. 2006 (CDP). Rarely c.fr.: capsules
immature 4, 7, 10, dehiscing 7, dehisced 4, 7, 9,
10.
Rather variable, the smallest (and immature) forms
often being difficult to separate from D. vinealis. Several
populations have been seen with leaves squarrose to recurved
(DTH 96-74, 96-496).
