*1: Near Mousehole, 1844, JR (PNZ) (Paton 1969a:
742-743).
*2: Near Helstone, 1840, CAJ (TRU) (Paton 1969a:
742-743).
Although var. gigantea was
recognised by Welch (1969) and Smith (2004) it may not be
worthy of taxonomic separation from var. antipyretica. Material
from Drift Reservoir (SW433289, low on trunks of Grey Willow
bushes at S. edge of Drift Reservoir, where normally
submerged, 14 Aug. 1995, DTH 95-264, 265, 266)
has some shoots showing characters of var. gigantea and others
indistinguishable from var. antipyretica.
Grows as lax wefts, often long (5 to 20 cm,
occasionally 35 cm), in shallow water (at least to 40 cm
depth) or where intermittently inundated. Habitat notes from
Cornwall are as follows. It grows attached to rocks (granitic,
gabbro, slate, serpentinite), masonry, firm soil or living or
dead wood, in standing water, trailing in flowing water, or
hanging vertically in trickling water e.g. at sluices. Most
records are from small to large streams and rivers. It is
widespread in the winter-flooded zones at the edges of Argal,
Cargenwen, College, Drift and Stithians Reservoirs, often
where exposed to wave action, but also occurs permanently
submerged in sheltered water of small lakes (e.g. at
Penjerrick). Along the lower R. Tamar it occurs at levels
subject to regular tidal flooding with fresh water whereas
plants growing at the highest levels further upstream may be
flooded only by high-stage flows. It grows unshaded, partly
shaded, or sometimes well shaded in woodland streams.
Fontinalis antipyretica is replaced by F. squamosa in streams
with really soft water, but both occur where hardness levels
appear slightly higher e.g. at Crowan and in the R. Tamar. It
tolerates moderate levels of eutrophication, but not the
highest levels where only Leptodictyum riparium
and Platyhypnidium
riparioides persist. It is most often found in pure
patches but sometimes close to Chiloscyphus
polyanthos, Cinclidotus
fontinaloides, Fontinalis squamosa,
Leptodictyum
riparium, Platyhypnidium
riparioides, or lichens. At Cargenwen Reservoir it is
co-dominant in a closed sward with Equisetum
fluviatile, Mentha
aquatica and
Pilularia globulifera, in shallow water that dries back in
most summers. See the account of Fontinalis squamosa
below for additional notes.
One record c.fr.: capsules dehisced 8 (Drift
Reservoir, vc1).
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