Cladonia cervicornis (Ach.) Flot.
Cladonia cervicornis (Ach.) Flot. subsp. cervicornis
Primary thallus made of basal squamules forming cushions up to 15 mm high, 5 mm long, ± rounded, sometimes nodulose and swollen or with margins indented, reflexed when dry, like flower bud (chrysanthemum flower). Upper surface green-blue, green-grey, grey-brown to green; lower surface white, greyish, sometimes tinged pink or mauve notably towards margins but not black nor dark towards the base. Podetia more or less abundant, to 1 cm tall, with shallow ± regular scyphus, without proliferation towards the center or margins and limited to one level, sparingly squamulose or smooth, without soredia. Apothecia as nodulose extensions on scyphus margin, brown, brown-red. Photobiont : trebouxioid. C-, K-, KC-, Pd+ red. Prefers basic coastal dunes (but not too calcareous), also on soil near the seashore and inland. See Cladonia subcervicornis, very similar but much darker grey, K+ yellow and Pd+ red and also Cladonia cervicornis subsp. verticillata of which the podetia form proliferating tiers in 2 or more levels from the center and mainly Cladonia firma which displays larger squamules markedly recurved at apices when dry, lower surface grey-violet and K+ yellow, very eldom fertile. N.B. This species is highly variable and may encompass several taxa (that were differently analysed by various authors). Seldom isolated and more often together with other Cladonia species thriving in the same habitat.