Thallus: foliose, up to 2 cm in diam., mostly irregular with confluent thalli; lobes: up to 2 mm broad, usually around 1 mm, about the same in length but sometimes much longer, ciliate; cilia: marginal, pale to black, always black in the outer part; upper surface: gray to dark gray; lobe tips mostly much darker, sometimes with a white pruina, sorediate; soredia: in helmet-shaped soralia, usually abundant, starting as holes just beneth the lobe tips; upper cortex: paraplectenchymatous; medulla: white; lower cortex: prosoplechymatous; lower surface: white to grayish; rhizines: white to black; Apothecia: not seen in Sonoran material; elsewhere up to 2 mm diam., stipItate; disc: sometimes thinly pruinose; ascospores: brown, 1-septate, Physcia-type, 10-23 x 7-10 µm; Pycnidia: sparse, immersed; conidia: subcylindrical, 4-6 x 1 µm; Spot tests: upper cortex K+ yellow, C-, KC-, P+ yellow; medulla K-, C-, KC-, P-; Secondary metabolite: atranorin in upper cortex.; Substrate and ecology: growing on trees and branches in fairly open situations, probably introduced by man; World distribution: widely distributed in temperate and boreal areas in all continents but more common at higher latitude up to 65ºN and 60ºS; Sonoran distribution: relatively frequent in upper montane forests of Arizona and coastal southern California and Baja California.; Notes: The species is easy to recognize by the cilia on the lobe margin and the helmet shaped soralia. In the Sonoran Region P. adscendens might be difficult to separate from some phenotypes of Heterodermia erinacea, and it is then necessary to study the upper cortex, which is prosoplectenchymatous in the latter. Physcia adscendens differs from P. tenellula in several aspects. The latter is much smaller and has a different type of soralia and hairs on the upper surface. 

Canada

Origin: Unknown/Undetermined

Regularity: Regularly occurring

Currently: Unknown/Undetermined

Confidence: Confident

United States

Origin: Unknown/Undetermined

Regularity: Regularly occurring

Currently: Unknown/Undetermined

Confidence: Confident

Marchandiomyces anamorph of Marchandiomyces corallinus parasitises bleached thallus of Physcia adscendens

Canada

Rounded National Status Rank: NNR - Unranked

United States

Rounded National Status Rank: NNR - Unranked

Rounded Global Status Rank: G5 - Secure

Reasons: "Physcia adscendens is common on deciduous trees, conifers, and granite and sandstone headstones in cemeteries from Canada and New England southward to Tennessee and Virginia" (Flenniken 1999).

Comments: Stable; See J. Thomson, 1963, The lichen genus Physcia in North America., Beihefte zur Nova Hedwigia, Heft 7. and also literature by R. Moberg.