Images of British Lichens
Cladonia ciliata Stirt.
var. tenuis (Flörke) Ahti (= f. flavicans (Flörke) Ahti & DePriest)
One of the 'reindeer lichens' (subgenus Cladina), variable in habit and colour (whitish grey or tinged yellow-green in var. tenuis (forma flavicans), but more strongly ash- or bluish-grey in the less frequent var. ciliata), resembling the more common C. portentosa but more delicate, with the majority of branches oriented in a single direction and often appearing "combed", colony often convex, forming small mounds, branching predominantly dichotomous at the apices (but by no means uniformly so), holes in the axes of the main branches usually inconspicuous, podetia reacting intensely orange-red with Pd (para-phenylenediamine); apothecia brown, like small buttons on the tips of the branches. Widespread and locally common at least in the north and west, in pinewoods, on heaths and moors, and on base-boor dunes.
Refs: Smith et al. (2009), 318; Purvis et al. (1992), 196; Ahti (1961), 57, plates 16,17 (photos, as C. tenuis); Nordic Lichen Flora (2013) 5: 29, 96 (photos, both variants, var. tenuis as f. flavicans); Dobson (2005), 135-6 (photo); Dobson (2011), 143-4 (photo); Britton (2008) 24 (photos, vars. ciliata & tenuis); Jahns (1983), 212-213 (photo, var. ciliata); van Herk & Aptroot (2004, 2013), 126-127 (photo, as Cladina ciliata); Aptroot et al. (2011), 60-1 (photos); Krog et al. (1994), 152 (photo); Stenroos et al. (2011), 124-5 (photo, var. ciliata); Wirth (1995), 1: 296, 297 (photo); Wirth et al. (2004), 72 (photo, ? var. ciliata); Wirth, Hauck & Schulz (2013), 1: 373, 395 (photo, var. ciliata); Thomson (1967) 146, plate 24 (photo, as C. tenuis); Lichen Atlas of the British Isles 2: 372, 373 (1996).
The two varieties look distinct in the field, in daylight, especially when growing together, but can be more difficult to distinguish during subsequent examination or from photographs. In shade, podetia may lose their "combed" appearance and much of the colour in the ultimate branches, but can be confirmed by chemical testing, most usefully with Pd if available (C. portentosa gives no reaction).
|Var. ciliata: in sandy pine-forest, Culbin Sands, Morayshire, August 2010. Lowest photograph shows apothecia.|
|Var. ciliata (left) and var. tenuis (right): together in sandy pine-forest, Culbin Sands, Morayshire, August 2010|
|Var. tenuis: in sandy pine-forest, Culbin Sands, Morayshire, August 2010|
|Var. tenuis: acid dune system, Cuthill Links, East Sutherland, April 2009|
|Var. tenuis (damp material): acid dune system, Findhorn, Morayshire, April 2009, note apothecia|
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Uploaded May 2008, substantially extended March 2012, last updated January 2016