Verrucaria erichsenii Zschacke

    Thallus crustose, usually smooth, sometimes minutely dotted or wrinkled, not cracked or just slightly, matt, blackish, brown-blackish, dark greenish-blackish, prothallus inconspicuous. Perithecia conical, well prominent, forming projections of 0.2-0.4 mm diam., apex often ragged or angular, often broadly open like a crater of an old volcano. Ascospores simple, oblong-ellipsoid, 8-12 x 5.5-7 µm. Rather rare, on rocks in the upper part of the Hydropunctaria (Verrucaria) maura black zone. Rather similar to Hydropunctaria (Verrucaria) amphibia but without ripples and wrinkles on thallus and located higher on the foreshore. Taxa of the Hydropunctaria (Verrucaria) maura group are much more common, their thallus are markedly cracked and their perithecia are flattened. N.B. The relationship between this taxon and Verrucaria ditmarsica, which would be a morph from calm estuaries, would benefit to be clarified through additional research, see discussion for this taxon.*