An alien from the Southern Hemisphere, reported by
Rumsey (2001) as well established when it was collected in
April 1991 from grotto with filmy-ferns near a waterfall in a
large private garden near Truro [the locality is at Tregye,
near Carnon Downs,
ca SW898398 (SW83E)]. This population was subsequently
categorised as a 'persisting introduction' (Blockeel 2010:
55). The species is a native of temperate regions of the
Southern Hemisphere. It has been found several times in
glasshouses in Britain but there
are no other reports of it becoming established in the open
air.
The record (from Tregye) was from a damp grotto in
the spray zone of a small waterfall, a feature created from
natural rock sometime in the 19th century. The grotto is at
the base of a steep, N.-facing bank, and is constantly damp
and sheltered. Within this, extensive mats of the filamentous
gametophytes of filmy-ferns (Trichomanes spp.)
occur, often pendant or on ledges, and the Achrophyllum occurs as
scattered plants creeping through these mats. The Cornish
plants had filamentous outgrowths from the leaves, but these
had not produced the typical 'L'-shaped gemmae of A. dentatum. Sporophytes
and gametangia were not seen on the Cornish
material.
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