Slideshow image
Acarospora rugulosa Korber
Family: Acarosporaceae
Acarospora rugulosa image
Thompson, J., 1997. American Arctic Lichens: The Microlichens.
Thallus areolate, the areolae to 1.5 mm broad, rounded or indistinctly lobate, convex, dark brown or reddish brown, dull; cortex 30-60 µm; underside pale. Apothecia solitary or 3-8 per areola, immersed, to 0.5 mm broad; margin often prominent; exciple 10-20 µm, I—; disk concave or flat, rough or umbonate, dark black-brown; epihymenium reddish brown; hymenium 110— 170 µm, 1+ red or sometimes blue; paraphyses 1.5-1.8 µm, tips dark brown capitate and 4-5 µm; spores very numerous, broadly ellipsoid, 3-5 x 1.8-2 µm.

Reactions: K—, cortex C+ red, P—.

Contents: probably gyrophoric acid, but not tested.

This species grows on a variety of acid rocks, usually those containing iron. In addition to its distribution in Europe, in Scandinavia and the Alps, it is reported from northeastern Greenland and Clyde Fiord, Baffin Island.

This species is similar to A. peliscypha, but with pale underside, higher hymenium, less-developed margin, and slightly shorter spores.