varying from under bark to dispersed over bark or other substratum, becoming smooth to irregularly granular-warty or soon bursting with small round or elongate soralia which enlarge and become capitate, sometimes forming a confluent granular soredial mass. Fruiting verrucae
0.5-1.2 mm broad, hemispherical, the tip granular and showing 2-3 disks; disks
rounded or irregular, reddish or reddish yellow, or waxy, slightly convex, often pruinose, sometimes the rather large ascal tips visible as darker, more gelatinous-appearing dots; hypothecium
pale, K—; hymenium
slender, 1.5-2 μm; asci broadly clavate; spore
single, hyaline, 2-celled, the cells easily separable, thick-walled, the outer thick walls lamellate and radiately striate, to 25 μm thick, the inner thin wall 2 fim thick, 200-407 x 72-136 μm.
Reactions: K-, C+ red, especially sore-dia and fruiting verrucae, KC+ red, P—; the spore walls faintly stain blue with I.
Contents: lecanoric acid, lichexanthone (UV+).
This species grows on soil, stones, moss, on the base of trees and on twigs of Alnus, Picea, Betula, rarely on cliff sides. It is circumpolar subarctic and boreal, in North America ranging from British Columbia to Cape Breton Island and in the North from Alaska to Labrador.
Although sometimes recognized as a separate species, V. kemensis is probably merely a very sorediate morph of this species.