Cladonia macilenta (images of British lichens)

Podetia usually small, often about 1cm in height, cylindrical, blunt-tipped, unbranched or, at most, sparsely branched, grey, podetial surface powdery-sorediate, often with a few small squamules below; basal squamules relatively small, incised, grey, becoming grey-green when damp; apothecia red, button-like on the tips of the podetia. Widespread and locally common but easily overlooked on damp stumps and tree-bases, often with C. coniocraea, and on wooden fence-posts.

Young material can be difficult or impossible to separate from young C. polydactyla, but it is generally much smaller, not always so intensely grey, much less variable, and does not develop cups. C. floerkeana is similar but usually larger and with conspicuous apothecia, and is granular rather than powdery sorediate.

Refs: Smith et al. (2009), 330; Purvis et al. (1992), 198; Nordic Lichen Flora (2013) 5: 53, 102 (photo); Dobson (2005), 131 (photo); Dobson (2011), 139 (photo); Fox, Guest & Harmer (2003), plate 3 (photo); Jahns (1983), 214-215 (photo); Whelan (2011), 76 (photo); van Herk & Aptroot (2004, 2013), 150-151 (photo, pycnidial stage); Aptroot et al. (2011), 88-9 (photos); Wirth (1995), 1: 298 as ssp. macilenta, 331 (photo, upper illustration only); Wirth, Hauck & Schulz (2013), 1: 375, 401 (photo); Krog et al. (1994), 160 (photo); Stenroos et al. (2011), 146-7 (photo); Valcárcel et al. (2003), 162-3 (photo); Puntillo (1996), plate 13 (photo, dry); Walewski (2007), 43 (photo); Lichen Atlas of the British Isles 2: 396 (1996).

FGBI: http://fungi.myspecies.info/all-fungi/cladonia-macilenta

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Images of British Lichens