Usnea subcornuta Stirt.

Nomenclatural data
Scott. Naturalist 6: 107 (1881).
Morphology
Thallus shrubby to subpendent; lateral branches lightly constricted at the point of attachment, branches with annular cracks; base pale; fibrils present, scarce to abundant; soralia usually large, with numerous isidiomorphs. Cortex glossy; medulla loose, contains subcortically (under the cortex) an orangish pigment.
Medullary chemistry
Chemotype (1) with stictic (K+ yellow to red, Pd+ orange) and norstictic acids as main substances (Fos & Clerc 2000).
Remarks
Has been considered as a synonym of U. cornuta, however, Clerc (1987b) indicated that this is a distict species characterized by the presence of orange pigment under the cortex. Morphologically similar to Usnea flammea (Fos & Clerc 2000), probably belongs to the U. fragilescens aggregate.
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Ecology and distribution
Europe (map legend)
Corticolous, on deciduous trees (e.g. Quercus suber), mostly on exposed branches of young trees (Fos & Clerc 2000). A rare species, known in Europe from a few southern localities only. Reported in Europe: Portugal, Russia (Caucasus), Spain.