Nephroma helveticum  

Thallus 3-4 cm diam., forming ± compact rosettes or irregularly spreading. Lobes 2-3 mm wide, ± elongate, loosely attached, the margins entire or with small, terete, isidia-like outgrowths and phyllidia which occasionally spread to the lamina. Fertile lobes ± scalloped (pectinate). Upper surface pale grey-brown to red- or dark brown, ± smooth, sometimes ± thinly pubescent. Medulla white. Lower surface dark brown to black, tomentose or densely pubescent. Photobiont cyanobacterial (Nostoc).
Anamorph: conidiomata pycnidia, rarely present. Conidia bacilliform, 3-4 x 1-2 µm in size.
Teleomorph: ascomata apothecia, frequent, to 8 mm diam., disc rounded to reniform, red-brown, margins conspicuously pectinate with teeth extending along the supporting lobe margins, thalline cuff narrow, the dorsal surface scabrid-pubescent, often markedly honeycombed. Ascospores 21-27 × 6-8 μm, fusiform, 3-septate.
Chemistry: thallus and medulla C–, K–, KC–, Pd–, (triterpenoids: major - T4, trace T1; unidentified accessory substances).