Thallus smooth or granular, superficial, fairly thick and nodular. Soredia and isidia absent. Photobiont Trentepohlia.
Anamorph: pycnidia not known.
Teleomorph: ascomata perithecial, ± superficial or partly covered by a thalline layer, 300-500 µm diam., dark brown to black with a shallow concave disc surrounding the ostiole. Involucrellum thick, dull purple, K+ dark grey to brown, composed of thick-walled ± elongate cells, the inner layers pinkish orange. Exciple yellow to pale orange. Interascal tissue composed of simple or rarely branched paraphyses. Hymenial gel I–, K/I– . Asci clavate-cylindrical, the wall thin throughout, functionally unitunicate (dehiscence by rupture of the apex, with no extruded inner layers, not blueing in iodine, 8-spored. Ascospores irregularly biseriate, 25-39 × 3.5-8 μm, 3- to 5-septate (up to 7-septate when over-mature), hyaline, narrowly ellipsoidal, smooth- and thin-walled.
Listed as Vulnerable (D2) by Woods & Coppins (2012). It is considered to be Nationally Rare and a former BAP Priority Species listed under Section 41 of the NERC Act 2006 and Section 2(4) of the NC (Scotland) Act 2004. It is recorded from a single site in Scotland and one or two sites in Cornwall. There appears to be some confusion regarding the Cornish site(s); what may be the same collection (made by the same person on the same date) has been assigned two different localities, Zennor Head [from the BLS database] and Botallack [according to the voucher specimen in the NHM].
Very similar to Porina mammillosa, another species of mine spoil sites, but with mostly 5-septate rather than 3-septate ascospores.
Reported from VC1 W Cornwall and VC88 Mid Perthshire.
On decaying mosses and soil on old mine spoil, in one case reported at the entrance of a low adit.