Fuscidea gothoburgensis (images of British lichens)

Thallus of pale- to brown-grey, often dispersed areoles, seated on a dark grey to black prothallus, soralia usually present, rounded, whitish- to greenish-grey; apothecia rare, brownish black, sessile, spores ellipsoid. Very local on hard, siliceous rocks in the north and west, mainly in the Scottish Highlands.

Refs: Smith et al. (2009), 409; Purvis et al. (1992), 253; Wirth (1995), 1: 400, 405 (photo, as F. maculosa, a variant now included in F. gothoburgensis).

Fuscidea is part of the very large 'Lecidea group' of lichens – crustose species with dark or black apothecia that lack distinct 'thalline' margins, though they will usually have differentiated 'proper' margins the same colour as the disk. Microscopic examination of mature apothecia (and sadly they are often not mature) is usually necessary even to be sure of the genus, and field identification of all but a few distinctive species is risky. Dobson (2011), pp. 236-7, gives an invaluable analysis of the component genera.

lastdragon.org

Images of British Lichens