Leprocaulon albicans (Th. Fr.) Nyl.
Nomenclatural data
Nyl. in Hue, Nouv. Archiv. Mus. 3, ser. 2: 248 (1890)
Stereocaulon albicans Th. Fr., De Stereocaulis et Pilophoris Commentatio, p. 36 (1857)
Morphology
Material from Greenland is white to pale grey, usually with a blue („cold“) tinge, sometimes forming a thick crust on the substrate reminding thalli of the Lepraria neglecta group, except for the presence of pseudopodetia and phyllocladia; pseudopodetia slender, darker near the base, usually less than 1 cm tall, with distinct central axis; phyllocladial granules coarse, hard, convex, 150–300 µm in diam. For a detailed description see Lamb & Ward (1974) and Ryan (2002).
Chemistry
Lamb & Ward (1974) distinguished three chemical strains: (I) atranorin, psoromic, conpsoromic and rangiformic acids together with unidentified fatty acids; (II) atranorin, protocetraric and rangiformic acids with unidentified fatty acids, plus up to 3 other unidentified substances; (III) atranorin, squamatic and baeomycesic acids and unidentified fatty acids. All examined specimens from Greenland contained squamatic, baeomycesic and roccellic/angardianic acids as in strain (III) but without atranorin.
Remarks
Strain III of L. albicans is chemically identical to the strain IV of L. subalbicans according to Lamb & Ward (1974) (see under that species). The morphological differences between these two species are often not distinct either, although the height of the pseudopodetia (a few mm in L. albicans and up to 1 cm in L. subalbicans) is considered diagnostic. Anatomically, the pseudopodetia of L. albicans have a distinct central axis whereas a central axis is not distinguishable in L. subalbicans (Lamb & Ward 1974). In practice the separation is often problematic due to poorly developed thalli.
Ecology and distribution

Greenland
On soil and bryophytes, sometimes overgrowing other lichens.
L. albicans is a southwestern to western species in Greenland, being rare in the High Arctic zone.
Species pages available
albicans | gracilescens | subalbicans
Literature
Saag, L., Hansen, E. S., Saag, A. & Randlane, T. 2007.
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