[3] The widely distributed type species, Dolichousnea longissima, is found in boreal regions of Asia, Europe, and North America.

Dolichousnea was originally circumscribed as a subgenus of the large genus Usnea, by Japanese lichenologist Yoshihito Ohmura in 2001.

[6] These are pseudocyphellae that resemble annular cracks, but the space between segments is swollen and surrounded by maculae (white spots on branch surface that form when the cortex tissue is thin).

[7] These pseudocyphellae differ from physical cracks, and seem to be formed due to pressure from the medullary hyphae beneath the cortex.

[10] Recent (2020) molecular phylogenetic analysis suggests that the taxon Dolichousnea trichodeoides represent an unresolved species complex.