Roccella fuciformis (images of British lichens)

Thallus fruticose, tufted with one to several, strap-shaped, hanging branches, the branches flattened, to 1.5 cm in width, lilac grey, ash-grey when dry, developing clusters of conspicuous, subspherical, white soralia; apothecia with black discs but very rare. On sheltered, often overhung, vertical rockfaces on sea-cliffs, very local and scarce on south-western coasts.

Refs: Smith et al. (2009), 826; Purvis et al. (1992), 553; Dobson (2005), 398 (photo); Dobson (2011), 402 (photo, poorly printed); Jahns (1983), 258-9 (photo); Church et al. (1996), opp. 32 (photo); Valcárcel et al. (2003), 346-7 (photo).

Usually in company with the somewhat more common Roccella phycopsis and perhaps over-recorded for flat-branched forms of that species (inferred from Church et al. (1996), pg. 82). The soralia react (bright red) with sodium hypochlorite (bleach), cortex non-reactive, whereas in R. phycopsis the cortex tests positive (pink) but the soralia are non-reactive. However, these rare species should generally not be damaged or collected.

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Images of British Lichens