Aspicilia candida (aka “Chalky Sunken Disk Lichen”)

Identification Charactaristics

Description: Thallus chalky white, almost blue-white, more or less circular, sometimes producing webby white lobes, or the thallus margin can be edged with a bluish black prothallus. Apothecia sunken or somewhat prominent, under 1 mm in diameter, sometimes, scattered, with pruinose-scabrose disks; margins darkish but pruinose; sportes 14-24 x 10-16 Um, 4-8 per ascus.  The thallus, like that of many arctic crustose lichens, can become eroded by sand & ice leaving only scattered patches & isolated apothecia.

Chemistry: All reactions negative (no lichen substances known).

Substrate: On calcarous rocks

Range: Subalpine to arctic

Bibliography: Lichens of North America, by Brodo, Sharnoff, & Sharnoff

Database Entry:  Distance Everheart 12-26-13