Tuckermannopsis orbata

Tuckermannopsis orbata is found in Asia and North America, growing primarily on the wood and bark of mostly birch and coniferous tree branches and twigs.

Nylander noted the species to be similar to what is now known as Tuckermannopsis ciliaris, but it lacked cilia, and did not react (in either the upper cortex or the medulla) to the potassium hydroxide chemical spot test (K−).

[3] Using a "temporal phylogenetic" approach to study the evolution of the Parmeliaceae, researchers proposed that certain genera, including Tuckermannopsis, should be merged with Nephromopsis,[4] but this suggestion was later disputed,[5] and the change in classification has not been universally accepted, particularly by some North American lichenologists.

[9] Tuckermannopsis orbata has a foliose (leafy) thallus that ranges in color from olive-brown to pale green when grown in the shade, to brown when exposed to the sun.

[9] Another potential lookalike, broadly distributed across the North American boreal forest, Cetraria halei, is distinguished by having more cilia on its margins and a distinct chemistry that includes alectorialic acid.

[13] Tuckermannopsis orbata is typically found on the branches and twigs of birch and conifer trees,[7] though it also occur on hardwoods, and, very rarely, on rock.

[10] In the Great Smoky Mountains National Park, it has been recorded on eastern hemlock, red spruce, yellow birch, and, at higher elevations, on Rhododendron.

Infection by the fungus results in the formation of a gall on the thallus surface, pale to medium brown in color and measuring 0.3–1.2 mm.

Thalli grown in shade conditions are paler than those grown in the sun.