Primary thallus disappearing; pseudopodetia erect, firmly attached to the substratum by expanded holdfasts, 2.5-4.0 cm tall, robust, rigid, woody, irregularly branched, decorticate, glabrous; phyllocladia lacking, replaced by whitish, granular soredia, effuse or in spathu-late apical expansions of the branches; cephalodia conspicuous, lateral, subglobose to becoming convolute-tuberculate or divided into verrucose masses, 1-2 mm in diameter; brown or glaucous-gray, sacculate with a solid core and well-developed cortical layer 35-75 µ thick, containing Nos toe or occasionally Scytonema. Apothecia terminal, concave or flat to becoming convex, large, 1.5-4 mm broad; disk dark brown to blackish brown; exciple 75-100 µ thick of hyaline to partly brownish gelatinized radiating structure; the fistulose hyphal lu-mina 1-2 µ wide; hypothecium 45-80 µ, brownish; hymenium 80-90 µ, hyaline, upper part brown; paraphyses discrete, 1—2 µ thick, simple or sparingly branched, tips brown, capitate, 3-4 µ; asci 70-80 x 12-15 µ, the walls 1+ blue; spores 8, elongate fusiform, straight or slightly flexuose, (3-) 5-7 septate, 40-65 X 3.5-4 µ. Conidia rod-shaped, straight, 4— 5 X 0.8 µ.

Reactions: K+ yellow, P —; soredia P+ sulphur-yellow.

Contents: atranorin and lobaric acid.

This species grows on rocks, rarely on soil, apparently in rather moist places as in the spray of waterfalls. It is widely circumpolar, disjunct in the northern hemisphere and in Uganda, Africa. In North America it is so far known from Alaska and Baffin Island, N.W.T.