Usnea articulata (L.) Hoffm.

Nomenclatural data
Deutschl. Fl. 2: 133 (1796).—Lichen articulatus L., Spec. Plant. 2: 1156 (1753)
Morphology
For a detailed description, see Swinscow & Krog (1976). The taxon is easily identified by the pendulous thallus with inflated sausage-like segments which are conspicuous at the older part of the thallus; fibrils scarce or absent; isidiomorphs present or absent; soralia absent but soredia-like propagules may be produced by pseudocyphellae; pseudocyphellae usually present, punctiform, sometimes enlarged. Cortex thin; medulla thin and extremely loose.
Medullary chemistry
Five chemotypes have been identified in East Africa (Swinscow & Krog 1976), one of which is known in Europe – with fumarprotocetraric acid as a main and protocetraric acid as an accessory substance.
Remarks
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Ecology and distribution

Europe (map legend)
The species is generally distributed in Europe in its western, central and southern areas where it grows on branches of deciduous or coniferous trees but may also scramble over low scrub vegetation in coastal sites (James 2003). Reported in Europe: Albania, Belgium (probably extinct), Czech Republic (probably extinct), France (probably extinct), Germany, Great Britain, Hungary, Ireland, Italy, Netherlands, Poland, Romania, Russia, Slovakia (probably extinct), Slovenia, Spain, Switzerland (probable), Ukraine.

Estonia
Listed in Estonia according to a record from the beginning of the 20th century in the vicinity of Tallinn, on the southern coast of the Baltic Sea (Mereschkowski 1913: one specimen, collected by Wasmuth); the herbarium sample is not preserved (Tõrra & Randlane 2007). Occurrence in Estonia is most doubtful due to its general distribution in Europe. Not recorded in Latvia and Lithuania either.