Usnea silesiaca Motyka

Nomenclatural data
Wydaw. Muz. Slask. Katowicach Dzial 3(2): 19 (1930).—Usnea madeirensis Motyka, in Tavares, Revista Biol. (Lisbon) 4: 131–134 (1964).
For a detailed description, see Clerc (1991, 2007), Purvis et al. (1992) and Halonen et al. (1998) (also under the name U. madeirensis). Thallus 6–12 cm long, shrubby, erect to pendulous, richly branched, branches somewhat interwoven; base thick, extensively blackened, with numerous annular cracks which may occur also in distant parts of the main branches; branches tapering, not constricted at the point of attachment; fibrils present, few to numerous; papillae present, dense on basal parts of main branches; soralia conspicuous, punctate to transversely elliptical to irregularly rounded, remaining discrete; isidiomorphs irregularly present, but usually absent on mature soralia. Cortex very thick (9–14%), mat; medulla very thin (7–12%) and compact.
Medullary chemistry
Chemotype (1) with salazinic (K+ yellow to red, Pd+ orange) acid as a main substance.
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Ecology and distribution
Europe (map legend)
Mainly corticolous, on various deciduous trees and, rarely, on rocks. Reported in Europe: Austria, Belgium (probably extinct), France, Germany, Great Britain, Italy, Luxembourg (probably extinct), Norway, Poland, Portugal, Spain, Sweden, Switzerland, Ukraine.