Images of British Lichens
Cladonia chlorophaea (Flörke ex Sommerf.) Spreng.
includes Cladonia chlorophaea sensu stricto; Cladonia grayi G. Merr. ex Sandst.
Podetia cup-like, grey-green, variable in shape but usually gradually tapered to the stalk, frequently proliferating from the cup margins, usually with granular soredia on the outer surface and interior of the cup; pycnidia minute, brown, on the cup margins, apothecia sessile or on short prolongations from the cup margins. Damp heathland, rotting stumps, dunes, widespread and common.
Refs: Smith et al. (2009), 323; Purvis et al. (1992), 201; Dobson (2005), 135 (photo); Dobson (2011), 143 (photo); Britton (2008) 30 (photo); van Herk & Aptroot (2004), 134-135 (photo), 146-7 (photo, under C. grayi / merochlorophaea); Krog et al. (1994), 151 (photo), also 159 (photo, grayi), 162 (photo, merochlorophaea); Wirth (1995), 1: 306 (as C. pyxidata subsp. chlorophaea), 307 (photo, upper illustration only, as C. pyxidata but correct identity fide Aproot et al., Lichenologist 33: 282 (2001)); Hansen & Anderson (1995) 27 (photo); Brodo et al. (2001), 247, 248 (photo); Hinds & Hinds (2007), 171-172 (photos, as aggregate); Thomson (1967) 105, plate 12 (photo); Lichen Atlas of the British Isles 2: 371 (1996); Walewski (2007), 41 (photo); McCune & Geiser (2009), 83 (photo).
C. chlorophaea forms a difficult complex of chemically defined taxa that are poorly defined morphologically. Numerous workers in Europe and North America have treated these taxa as separate species and some studies, e.g. Ferry & Pickering (1989), Lichenologist 21: 67-77, at Dungeness, confirm a degree of correlation with morphology and ecological preferences at the local level. However, there is indication of interfertility between taxa (Culberson, et al. (1988), Amer. J. Bot., 75: 1135-1139) and it remains to be shown that these chemically defined races represent internationally cohesive biological taxa, or independent lineages if one accepts the strict cladistical view usually assumed by DNA workers.
James (in Smith et al., 2009, under C. chlorophaea) provides a summary of those taxa accepted as British (asahinae, chlorophaea s.s., cryptochlorophaea, grayi, merochlorophaea). Thin layer chromatography (TLC) is required for accurate identification of chemical variants, but simple chemical tests and examination under UV light allow arbitrary, provisional identifications, and James's account is followed here. Below are shown:
C. chlorophaea, sensu stricto, which according to various workers is less restricted to acidic habitats and is widespread in Britain, C-, K-, KC-, Pd+ red, medulla not fluorescent under UV light. The photographed material has distinctly denticulate cup margins.
C. grayi, said to be scarcer and more strictly confined to acidic habitats, C-, K-, KC-, Pd+ red, medulla fluorescing bright blue under UV light (not to be confused with reflection of visible blue and violet light off the lichen surface). Material shown here appears to be a reasonable match to the description and photograph of Norwegian material provided by Holien et al., Gunneria, 51: 7-26 (1985), including presence of podetial squamules. The cup margins are distinctly pinkish. It should be noted that the name 'C. grayi' has commonly been used in a broader context, covering C. merochlorophaea and other taxa.
C. humilis, with short podetia, wide cups and large, persistent basal squamules, could be included within this aggregate. The complex is commonly also confused with the C. pyxidata group, which have corticate granules within the cups.
|Mixed population (C. chlorophaea s.s. (mainly to right) and C. grayi (mainly to back and left), on old heather (Calluna) twigs, Thetford, Norfolk, February 2010.|
Arrowed specimens were chemically tested and checked with UV illumination.
|On peaty debris, Foss, Perthshire, April 2003, not identified beyond aggregate|
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Uploaded March 2008, substantially revised July 2010, last updated March 2012 (first hosted at www-biol.paisley.ac.uk, December 2006)