Pseudephebe pubescens

Linnaeus first described Lichen pubescens in 1753.[1] Maurice Choisy transferred it to the genus Pseudephebe in 1930. It is usually distinguished from P. minuscula due to P. pubescens preferring a moister habitat, and its branches are more terete and lack the irregularities of P. minuscula.[2] The morphological and ecological differences between the two species are often overlapping, and it can be difficult to truly distinguish the two without molecular analysis.[3][4]

Pseudephebe pubescens is a fruticose lichen that forms decumbent mats made of isotomic-dichotomous branching thalli. The branching occurs frequently and weaves around itself, leading to the woolen appearance. Dark brown to black in color and shiny.[5] Apothecia are rare, but are rarely greater than 6 mm in diameter and have the same appearance as the rest of the thallus.[6] The species lacks isidia, soredia, and pseudocyphellae.[3] Pycnidia occur in great numbers on tubercles with conspicuous ostioles. It is not known to produce any secondary metabolites.[7]

Pseudephebe pubescens is found specifically on acidic or silicate rocks in temperate-alpine or sub-arctic regions.[1] It has circumpolar sightings, being found from the Canadian territories, throughout the United States, and sometimes in alpine Mexico.[1] It has been known in Europe, but recently discovered in China[4] and even been found in the Andes and in Australia.[8] It has been known to grow upon wood occasionally. Pseudephebe pubescens tends to be in more temperate environments than P. minuscula.