Cladonia cariosa

Podetia 0.5–1.5 (–2) cm tall, grey-green, sometimes tinged brownish; scyphi absent, often sparingly branched above, the surface partly decorticate, distinctly longitudinally fissured with large, gaping cracks, often net-like, ± covered with numerous small corticate granules, sometimes with scattered squamules; soredia absent. Basal squamules mostly rather small, 1-3 mm long, ± erect, the margin entire or incised, with dark brown pycnidia on the upper surface, often grey-tinged below. Apothecia usually abundant, dark brown, at apices of podetia and branches, usually larger than the width of branches, often clustered and ± corymbose. Three chemotypes occur in Britain and Ireland: C–, K+ yellow, KC–, Pd–, UV– (atranorin), widespread but local; C–, K+ yellow, KC–, Pd+ rust-red, UV– (atranorin, fumarprotocetraric acid), rare; C–, K± yellow, KC–, Pd–, UV– (atranorin, rangiformic acid), very rare. 

Readily recognised by the longitudinally multi-fissured podetia and large, clustered, terminal brown apothecia. C. symphycarpa is similar but has larger squamules and broader podetia (which are rarely seen), and tends to occur on more strongly calcareous substrata.Sterile squamule mats occur but are difficult to separate from juvenile C. rangiformis squamules which often accompany C. cariosa. See also the very rare Cladonia peziziformis.