Cetraria juniperina (L.) Ach.

    Foliaceous thallus, loosely attached to its substrate, in rosettes or small bushes, 3-5 cm in diameter, formed of more or less erect and slightly canaliculate lobes, serrated margin with pycnidia. Upper surface, bright yellow if in the sun, yellowish-green if in the shade, lower surface veined, pale yellowish, pale brownish, yellowish-white with some simple or squarrous, whitish rhizines. Frequent apothecia, lecanorine, submarginal or laminal, 2-6 mm in diameter, flat or concave and smooth disc, reddish-brown, smooth margin, yellow, often bordered by digitations bearing black pycnidia. Claved asci with a very large thollus, 8 spores, 30-40 x 15-20 µm according to our measurements. Ascospores simple, hyaline, broadly elliptical or subglobose, 5-6 x 6-8 µm according to our measurements. Marginal pycnidia frequent, black, often at the top of a digitate outgrowth, conidia in "bottle", 6-8 x 1-2 µm. Photobiont: chlorococcoid. Cortex: K-, C-, KC+ yellow, P-; medulla: K-, C-, KC-, P-, UV+ dark red. Subarctic or subalpine species occurring on the calcareous soils of alpine meadows and more rarely on the branches of trees (Juniperus,..) or bushes of the high mountains (N.B. These two ecoforms are no longer currently distinguished at the rank of species).