Usnea dasaea Stirt.

Nomenclatural data
Scott. Naturalist 6: 106 (1881).—Usnea dolosa Motyka, Lich. Gen. Usnea Stud. Monogr., Pars Syst. 2(1): 494 (1937).—Usnea galbinifera Asahina, J. Jap. Bot. 38: 257 (1963).—Usnea spinigera Asahina, Lich. Jap. 3: 85 (1956).—Usnea spinulifera (Vain.) Motyka, Lich. Gen. Usnea Stud. Monogr., Pars Syst. 2(1): 518 (1937)—Usnea undulata Stirt., Scott. Naturalist 6: 104 (1881).
For a detailed description, see Clerc & Herrera-Campos (1997) and Clerc (2007). Thallus shrubby to subpendant, 2–15 cm; base pale, without distinct annular cracks; secondary branches slightly to distinctly constricted at their point of attachment; fibrils present, occasionally numerous, spinulous; papillae absent on all branches; soralia punctiform to slightly elliptic longitudinally (especially on terminal branches), with isidiomorphs. Cortex glossy, thin; medulla thick, dense to compact.
Medullary chemistry
Chemotype (1) with galbinic, norstictic and salazinic acids as main substances (K+ red, Pd+ orange).
Belongs to the U. fragilescens aggregate.
Presence of numerous fibrils while papillae are totally absent are characters to distinguish this taxon from other shrubby species. May be confused with U. hirta, which, however, has numerous isidia all over the thallus, and different chemistry.
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Ecology and distribution
Europe (map legend)
Mainly corticolous, but may also grow on rocks (Clerc & Herrera-Campos 1997). Worldwide (Clerc 2007); distribution in Europe is southwestern (Fos & Clerc 2000). Reported in Europe: France, Italy (?), Portugal, Romania, Slovenia, Spain.