*1: Trengwainton,
Penzance, 1860, WC (NMW) (Paton 1969a:
704).
*2: Boconnoc near
Lostwithiel, 1791, EF (BM) (Paton 1969a:
704).
Habitat notes from C&S are as follows. On rocks
(and firm soil, exposed roots, etc.) in and beside
quick-flowing soft-water streams and rivers, from close above
summer water-level to shallowly submerged (to ca 20 cm depth); often
partly shaded to well shaded (e.g. in woods, Grey Willow
carrs). Common in a stream with much pollution from old copper
mines, where it is the only submerged bryophyte; also in
streams in china-clay district prone to heavy clay
sedimentation, where again often the only submerged bryophyte;
apparently intolerant, however, of eutrophication of streams
due to sewage input. On rocks and hard soil in upper part of
inundation zones of reservoirs. On vertical granitic and slaty
rocks trickling with water, in shade of deciduous woodland.
Small amount on firm soil of stream bank ca 20 cm above winter
water-level. On wet china clay at unshaded edge of concrete
settling tank. In marsh developing on floor of china-clay pit.
Strongly toothed form on track edge on china clay spoil (with
Nardia scalaris).
On soil among stones of damp path in woodland and on a damp
track near wood edge. Occasionally in open mires and acidic
flushes with sphagna. Flushed granitic rocks on exposed
sea-cliffs (with Blindia acuta, Solenostoma
gracillimum); flushed slaty rocks in quarry above
sheltered riverbank, part shaded by trees. Once shallowly
submerged in runnel in mesotrophic mire, with Solenostoma
gracillimum. Often in pure patches but frequent associates
include Chiloscyphus
pallescens, Chiloscyphus
polyanthos, Fontinalis squamosa,
Hygrohypnum
ochraceum, Marsupella emarginata
var.
emarginata, Racomitrium aciculare,
Platyhypnidium
riparioides; others recorded include Leptodictyum riparium.
Commonly with gemmae. With perianths: 10. No DTH
record c.fr.
