Ochrolechia upsaliensis

The lichen was formally described as a new species by Carl Linnaeus in his 1753 work Species Plantarum. He placed it in the eponymous genus Lichen, as he did with all of the 80-odd lichens he described in this work.^[4] Abramo Bartolommeo Massalongo transferred the taxon to the genus Ochrolechia in 1852.^[5]

The thallus of Ochrolechia upsaliensis is white to grayish-white, and crustose; the thallus thickens with age. The texture of the thallus surface ranges from smooth to granular. The lichen produces abundant apothecia; these reproductive structures are shallowly saucer-shaped, measuring 0.5–3 mm in diameter, with a pale-buff disc. The ascospores typically number 8 per ascus; they are ellipsoid with dimensions of 31–69 by 23–37 μm.^[6]

Ochrolechia upsaliensis reacts negatively to all standard lichen spot tests.^[6]

Ochrolechia upsaliensis has a Northern Hemisphere distribution, having been reported from Europe, arctic areas of Alaska and Canada, Greenland, and mountainous areas of the United States. It also occurs in mountainous areas of Europe.^[6] There, it prefers habitats with calciferous soil and plant debris, and grows optimally above the treeline. In the Alps, where it is widespread, Ochrolechia upsaliensis reaches the Nival zone.^[7] It typically overgrows mosses, sedges, grasses, or grows on the ground; less frequently, it has been recorded growing on rock.^[6] In Greenland, it is a component of the lichen-rich biological soil crust.^[8]

The species is host to the lichenicolous fungus species Sclerococcum deminutum.^[9]

• List of lichens named by Carl Linnaeus