forming more or less continuous crusts on soil, erect or partly decumbent, small, 2-4 mm tall, 0.25-0.50 mm thick; irregularly branched, terete or partly slightly flattened, white or ashy white, dull, with soft but not tomentose surface, base without rootlike structures; pseudopodetia
more or less uniformly covered with concolorous irregular poorly defined small lumps 0.1-0.2 mm diameter. With no central axis, the whole structure homogeneous of compactly interwoven, darkened, opaque, somewhat leptodermatous hyphae of 3-4 μ diameter; those on the outside loose and floccose, the algae mostly in groups near the surface, chiefly in the small lumps.
Reactions: Very variable, dependent on the strain. Strain I K —, P + intense yellow; Strain II K-I- brownish or brownish-yellow, P + red; Strain III K + indistinct yellow to strong yellow or sometimes orange-yellow to red; Strain IV K+ yellow, faint brownish yellow or K— , P + intense yellow.
Contents: Strain I, atranorin, psoromic, conpsoromic, and divaricatic acids + unidentified substance; Strain II, atranorin, protocetraric acid, unidentified fatty acids, and 2 other substances; Strain III, atranorin, thamnolic acid, and unidentified fatty acids; Strain IV, atranorin, squa-matic, and baeomycesic acids and unidentified fatty acids.
The type specimen of the species from Chile belongs to Strain I. The strain which reaches the arctic is Strain IV.
This species grows on soil or on soil over rocks or in crevices of rocks. It is reported by Lamb and Ward from the Americas, Strains I and II from Chile, Peru, and Argentina, Strains III and IV in North America, the latter in Alaska and Greenland.
L. albicans (Th. Fr.) Nyl. differs in having distinctly developed phyllocladial granules, a well-developed central axis and a more chalky white color. In its Strain III with atranorin, squamatic and baeomycesic acids, and unidentified fatty acids it resembles Strain IV of L. subalbicans. It is reported in Strain III from Alaska, Mt. Roberts, Juneau, Krog, by Lamb and Ward. This suggests that any collections from further north should be carefully checked for each.