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Lepraria albicans (Th. Fr.) Lendemer & Hodkinson
Family: Stereocaulaceae
[Leprocaulon albicans (Th. Fr.) Nyl. ex Hue,  more]
Lepraria albicans image
Thallus: fruticose, without persistent primary thallus, extensively covering the substrate in a continuous or discontinuous pattern, sometimes low and congested-pulvinate and forming a dense crust-like growth central axis: well differenttiated, cloudy and opaque, yellowish-gray, composed of longitudinally parallel hyphae 2.5-3.0 micrometer diam. with outer wall thinner than lumina; outer mantle 15-25 micrometer thick, of lax hyphae 2.5-3.0 micrometer diam., running chiefly longitudinally, enclosing scattered groups of algae surface: white, whitish gray, bluish white or cream-colored, without distinct yellowish tinge, chalky, subtly whitish arachnoid-tomentose or partly glabrous, brown or brownish towards base, where often ± dying pseudopodetia: (2-) 1 (-2.5) cm long, 0.2-0.3 mm thick, crowded-caespitose, erect or interwoven, terete, not dorsiventral; sparingly branched (not dichotomously), not dendroid-plumose; without root-like basal structures phyllocladial granules: distinctly developed, subglobose, 0.10-0.25 mm diam., chalky-whitish to grayish, dull, subtly powdery but not sorediate, with central mass of algae, without medulla, surrounded by a cloudy and semi-opaque tissue of loosely interwoven and floccose hyphae forming an envelope 12-30 um thick Spot tests: thallus K- to + faint to distinct yellow, C-, KC-, P+ persistent intense yellow (strains I and III), orange-yellow (strain I) or P+ intense orange-red to scarlet-red (strain II); UV- or (strain III [non-Sonoran]) + blue-white Secondary metabolites: atranorin (sometimes minor), fatty acids (including rangiformic acid in strains I and II), plus (strain I) psoromic acid chemosyndrome, (strain II) protocetraric acid, or (strain III [non-Sonoran]) squamatic and baeomycesic acids. Substrate and ecology: on detritus with mosses, or over mosses, on open rock faces or in rock crevices, sometimes on soil among grasses between rocks, in quite exposed situations or in moderately shaded places World distribution: North America in the west and South America Sonoran distribution: California, Arizona and Chihuahua, 1800-2250 m (all Strain 1).