Images of British Lichens
Fuscidea cyathoides (Ach.) V.Wirth & Vězda
Thallus pale grey, usually with brown tinges, to grey-brown, cracked areolate, margins often limited by a black prothallus that marks out clear boundaries with other thalli of the same or other species, soralia usually absent (var. cyathoides, shown here), sometimes with scattered, yellowish or greenish soralia (var. sorediata); apothecia brownish black, sessile or initially set in the thallus, margins initially conspicuous, paler, often flexuose, later often obscured as the apothecium develops, spores kidney-bean shaped. In lichen mosaics on hard, siliceous rocks, northern and western, often very common. Chemical tests (K+ brownish-yellow, Pd+ red) help separation from rarer species of the genus.
Refs: Smith et al. (2009), 408; Purvis et al. (1992), 253; Dobson (2005), 177 (photo); Dobson (2011), 183 (photo); Allen (2007), 38 (photo); Dalby & Dalby (2005), 20 & 41 (photos); Whelan (2011), 96 (photo); Wirth (1995), 1: 400, 401 (photo); Wirth, Hauck & Schulz (2013), 1: 487 (photo); Moberg & Holmåson (1984), 126 (photo); Holien & Tønsberg (2008), 161 (photo); Valcárcel et al. (2003), 192-3 (photo); Puntillo (1996), plate 18 (photo).
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.
|On stabilised coastal shingle, Kingston on Spey, Morayshire, August 2010 (BLS meeting)|
|On upland boulder, Gleann Leireag, West Sutherland, August 2010|
|On exposed rock, Great Cumbrae, Clyde Isles, April 2010|
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Uploaded March 2011, last updated January 2016