Similar to Heterodermia obscurata but with a thallus with narrower lobes and a different chemotype (norstictic acid, atranorin, zeorin), resulting in reactions of C–, K+ yellow→red (crystals), KC+red, Pd+ orange and UV–. Further research is needed on the identity of these populations.
BLS map: click here.
Assessed by Woods & Coppins (2012) as Vulnerable (D1+2).
Only known from the islands of Tresco, Bryher and St Martin (VC01 W Cornwall and Scilly Is).
On soil in exposed coastal turf, with Cladonia species and sometimes alongside Heterodermia leucomela.