First vice county records of the s. l. species (see below):
*1: Mean Rock, N. of Constantine, 1837, EAW (TRU) (Paton 1969a:
730).
*2: Helman Tor, 1891, RVT (B) (Paton 1969a:
730).
First vice-county records of R. heterostichum s.
str.:
*1: Zennor, 1924, PWR (Blockeel 1991: 34, 1992:
26).
*2: BrownWillie,
1922, AS (Blockeel 1991: 34, 1992:
26).
See notes above. Taxonomy of this group was
elucidated by Frisvoll (1988). British specimens were revised
by Blockeel (1991), who found that R. obtusum appears to be
no more than a muticous form of R. heterostichum which
probably does not merit treatment as a separate species.
Grows in tufts or forms small to rather large
patches. Habitat notes from C&S are as follows. Confined
to hard rock surfaces (granitic, gabbro, slates), typically on
horizontal to inclined surfaces or arising from small
crevices, more rarely from a very thin layer of overlying soil
or a bryophyte mat. Recorded from natural outcrops and
boulders (e.g. on hillsides, heathland, reservoir edges
including upper part of inundation-zone), quarried rocks,
areas of old quarry- and mine-spoil, old and rather recent
china-clay spoil, rocks in 'hedges', walls, and rock of
gravestones and grave surrounds. Grows in fully insolated
sites and lightly shaded at wood edges, less often partly
shaded, e.g. in open deciduous woodlands. Normally restricted
to rock substrates, but a single record on firm gritty china
clay waste on unshaded bank at quarry edge. Often common in
areas with much exposed granite, but much scarcer elsewhere.
Most of the records furthest from the granite districts are on
old walls, gravestones, or isolated boulders, in some cases
perhaps a result of the moss having been transported by man
attached to a boulder. Often grows with Grimmia trichophylla
and lichens; other frequent associates include Andreaea rothii, Dicranoweisia cirrata,
Hedwigia stellata,
Racomitrium
fasciculare, less often Ptychomitrium
polyphyllum, Racomitrium
lanuginosum.
Frequently cfr; capsules immature 1-5, 9-12;
dehiscing 3, 5; dehisced 3-5, 7-9, 11.
