Megaspora verrucosa (Ach.) Hafellner & V. Wirth var. mutabilis (Ach.) Nimis & Cl. Roux

Thallus grey to white, matte and appearing chalky, continuous, with large warts, many of which are topped by 1-2 inset apothecia, sometimes outlined by a white prothallus; apothecia 0.5-1.5 mm wide, the rim usually not clearly offset from the thallus, the disc dark grey or olive grey; rim with an algal layer and a proper exciple, both grey-discoloured at the surface; hymenium about 100  µ high; upper hymenium with medium to dark olive pigments, K+ gold-green or gold-brown, lacking granules; asci thin-walled except for the thin, IKI+ light blue, crescent-shaped tholus at the apex; spores 8 per ascus, 42-50 × 25-30  µ, the walls 1.5-2.5  µ thick.

Reactions: All spot tests negative.

Contents: No known lichen substances.

Habitat: Base of large Pseudotsuga trunk. Lower elevations.

Similar Species: Resembles certain Pertusaria species that could be expected to occur in the study area, none of which have greenish pigments in the upper hymenium.

Specimens: Goward 98-02.

Local Status: Occasional.