Mycotaxon 49: 427 (1993).

Basionym: Cetraria juniperina var. canadensis Räsänen, Ann. Mo. Bot. Garden 20: 12 (1933).

Type locality: Canada, Kamloops, Fish Lake, Rainbow, ad ramos pini Merryani, 4/IX 1931, Viljo Kujula (H - holotype).

Thallus: foliose, intensely bright and deep yellow, rosette-like, sometimes with long, narrow or broad, often errect lobes, occasionally slightly canaliculate, generally with raised lobe tips, branches usually short. Projections lacking. Epicortex hyaline, 1 - 2 µm. Cortex 12 - 27 - 50 µm thick with uppermost cells isodiametric, 3 - 3.6 - 5 µm diameter, cells of the two lower layers usually elongated, 3 - 6 - 7 / 3 - 4 - 5 µm diameter. Medullary hyphae 3 - 4 - 6 µm thick. Algal layer 10 - 15 - 24 µm thick. Apothecia common, laminal, thalline margin crenulate, asci broadly clavate 27 - 33 - 40 / 10 - 13 - 15 µm, tholus with moderate amyloid reaction, spores subspherical 5 - 6 - 7 / 4 - 4.5 - 5 µm. Pycnidia almost spherical 90 - 110 - 120 / 100 - 110 - 120 µm, immersed, pycnidial wall 10 - 14 - 20 µm with ca. three layers of isodiametric cells 2 - 2.5 - 3 µm diameter, the uppermost parts black, closely connected to the cortex, lower parts with pale brown pigmentation, pycnoconidia citriform, 3 - 3.5 - 4 / 2 µm (Mattsson 1993: 32).

Photobiont: 7 - 15 - 19 µm diameter (Mattsson 1993: 32).

Chemistry: Usnic acid in the cortex, pinastric acid and vulpinic acid in the medulla. Traces of other aromatic substances very rarely observed with TLC (Mattsson 1993: 32).

Ecology: In moderately xeric to mesic, coniferous forests. Corticolous, mainyl on conifers, often abundant on branches of Pinus ponderosa, P. contorta and Pseudotsuga menziesii in forests dominated by these species (Mattsson 1993: 32).

Molecular data: Genbank

Distribution type: Mountains of western North America.

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