*1: Hayle Sands, 1861,
WC (GL) (Paton 1969a: 753).
*2: Polzeath, 1958, TL
(Paton 1969a: 753).
Forms low patches (smooth mats) or straggles
through grasses, herbs and other bryophytes. Habitat notes
from C&S are as follows. Mainly coastal and commonest on
calcareous sand in and near sand-dune areas, in unshaded or
lightly shaded grassland (or partly shaded by grasses, or
lightly shaded by edges of scrub), or on banks, in
free-draining sites but avoiding the barest and driest places.
At Holywell it is locally abundant on semi-fixed dunes,
dominating the ground layer in some areas at the base of Ammophila arenaria. R. megapolitanum extends
from the dunes to other coastal areas that receive blown sand,
including the base of 'hedges' near dunes (e.g. at Riviere
Towans, where often part-shaded by brambles and tall grasses),
hillslopes immediately downwind of dunes or above beaches and
on an old grave in Lelant Cemetery. In other coastal areas it
occurs on thin soil over slaty or serpentinite rocks on open
slopes of coastal headlands, often on south-facing slopes and
sometimes in exposed places.
There are only a few records inland in Cornwall:
large patch on gravelly surface of grave in churchyard ca 0.5 km inland; on
top of wide mortared-stone wall near stream, part-shaded by
deciduous trees (St Mawgan); on soil of disturbed ground in
area of metalliferous mine-spoil (Porkellis
Moor).
Associates at coastal sites include Bryum dichotomum, Syntrichia ruralis
var.
ruraliformis,
Syntrichia ruralis var. ruralis; Ammophila arenaria, Festuca rubra. One of
the few inland records was with Brachythecium
rutabulum,
Cirriphyllum crassinervium.
Commonly c.fr.: capsules immature 1, 12; dehiscing
1, 2 [3], 11; dehisced 3-5.