Cladonia gracilis  

Thallus: podetia 1-6 cm tall, slender, 0.5-1.5 mm diam., greenish grey, or often olive to dark brown, often becoming dark brown-black towards the base, unbranched or sparingly branched, pointed at apices or usually some with a terminal, ± regular, shallow scyphus 1-2 mm diam., not perforate, often with dentate margins, sometimes proliferating from the rim; surface smooth, corticate, usually conspicuously but finely areolate (×20 lens), attached squamules usually absent or scarce. Basal squamules up to 2 mm diam., indented, mostly disappearing.
Anamorph: conidiomata pycnidia,  dark brown, frequent.
Teleomorph: ascomata apothecia, dark brown, at apices of podetia, rather rare.
Chemistry: thallus C–, K–, KC–, Pd+ red, UV– (fumarprotocetraric acid).