Verrucaria margacea s. lat.
Observation - Verrucaria margacea s. lat. - UK and Ireland. Description: On siliceous rock shallowly submerged in stream at 500m. Thallus non-gelatinous, brown where well developed, mottled white and grey where thin (prothallus?). Involucrellum broadly conical, reaching the substratum, with brown-walled cells in the angle betw
On siliceous rock shallowly submerged in stream at 500m. Thallus non-gelatinous, brown where well developed, mottled white and grey where thin (prothallus?). Involucrellum broadly conical, reaching the substratum, with brown-walled cells in the angle between the involucrellum and the base of the exciple (as in V. margacea s. str.). Ascospores simple, colourless, ellipsoid, 23-30 x 14-16µm (mean 26.3 x 15.0µm), length:width ratio 1.5-2.1 (mean 1.8).