*1: Muddy ground at
edge of stream, St Cadoc, Padstow, July 1954, EFW (Warburg
1958: 481, Paton 1969a: 731).
*2: Grassy roadside S.
of White Cross, Wadebridge, July 1961, JAP
(BBSUK) (Warburg 1962: 371, Paton 1969a:
731).
Occurs as scattered plants, in small patches, or
where commoner forms low turfs. The plants grow quickly and
mature within a few months from late spring to autumn, on
drying mud or damp soil (silty, clayey or loamy; mildly acidic
to circumneutral; wet to damp, rarely rather dry; unshaded,
less often lightly or part shaded). Large populations occur in
the inundation zones beside reservoirs (Argal, College, Drift
and Stithians Reservoirs, Upper Tamar Lake), the plants
evidently reappearing from a persistent spore-bank in the
substrate in those years when water levels are low. Sparsely
scattered small populations (sometimes a single isolated
plant) have also been recorded from damp soil or mud in
various other places that are wet in winter but dry in summer:
several times in ruts, hollows or larger ephemeral pools along
old tracks, twice in cattle-poached ground near a gateway into
pastures (at one site most plants were on steeply inclined
edges of the hoof-prints), ruts in damp edge of a stubble
field, on partly shaded banks near the Bude Canal and beside a
damp lane, and once a rather dry bank in a small woodland
clearing.
On reservoir mud A. patens often lacks
close associates, but it was frequently also recorded with Pseudephemerum
nitidum, less often Bryum klinggraeffii,
Trichodon
cylindricus, Leptobryum pyriforme,
Pohlia annotina, Riccia sorocarpa, Littorella uniflora.
Associates recorded with small populations on damp tracks etc.
were Dicranella
staphylina, Pseudephemerum
nitidum, Gnaphalium
uliginosum, Juncus
bufonius, Agrostis
stolonifera and various other herbs and
grasses.
Usually c.fr. except when plants immature; capsules
immature 6-11; dehiscing [8],
9-11.
