Cladonia subcervicornis (Vain.) Kernst.

    Primary thallus forming dense mats or small cushions of erected squamules, rather thick, up to 2 cm tall, squamules tips almost straight, markedly and minutely incised, whitish, which gives it a "frosted" appearance, upper surface apple-green when moist, pale grey-green when dry, lower surface whitish to brown or black towards the base. Podetia rare, up to 15 mm tall topped by a large scyphi with small and brown apothecia at rim. Pycnidia frequent. Photobiont : trebouxioide. C-, K+ yellow, KC-, Pd+ red. Species growing on humus, particularly pockets in crevices on acid rocks and boulders on Calluna heathlands of the aerohaline zone. Quite similar to Cladonia strepsilis  that is C+ green. Also watch out for Cladonia cervicornis which is not so green and K-.