Slideshow image
Verrucaria devergens Nyl.
Family: Verrucariaceae
Verrucaria devergens image
Lucy Taylor  
Thompson, J., 1997. American Arctic Lichens: The Microlichens.
Thallus immersed in the rock, forming a whitish color on the rock, sometimes with a black bordering line. Perithecia half immersed in the rock, 0.25-0.3 mm broad, hemispherical; ostiole with small, not sunken aperture; exciple entirely black or brownish black, even in thickness or with the tip thicker; hymenial gelatin 1+ reddish; spores elongate-ellipsoid, 30-36 x 11-18 µm.

This species grows on calcareous rocks. It is a circumpolar arctic species which is known from Scandinavia, Novaya Zemlya, and the American Arctic.