*1: Lelant, 1921, Watson
(Rilstone 1926);Carbis
Bay,
1961, JAP (BBSUK) (Paton 1969a: 724).
*2: Polperro, 1931, FR
(BM) (Paton 1969a:
724).
As
noted under species
heading , treated as B. convoluta var. commutata in the older
literature (e.g. Smith 1978: 151), then as merely a luxuriant
form or synonym of B. convoluta in recent
decades (e.g. T.L. Blockeel in Hill et al. 1992: 262,
Blockeel & Long 1998: 90), until Frahm & Ahmed (2004)
revived it as a distinct species (which should be known at
species rank as B. commutata not
B. sardoa: see Frahm
2004). Intermediate plants appear to be common in Cornwall and
elsewhere in the British Isles, so that varietal status seems
more appropriate and for this reason it is treated as a
variety here following Hill et al. (2006,
2008).
Plants showing characters of var. sardoa (larger size,
leaves with undulate margins) are common in Cornwall, often
growing in damp, nutrient-rich sites on soils, e.g. in
gardens, on soil heaps, or at path sides. They apparently also
occur more often than var. convoluta as dense and
sometimes rather deep cushions on old mortar of walls or on
concrete, evidently persisting as a short-lived perennial
rather than occurring as an ephemeral or annual colonist like
the smaller forms of
var. convoluta
that are typical on partly bare soil substrates. Also recorded
from an old mine site.
Frequently c.fr. Capsules: immature 2, 4, 7,
dehisced 11.