Parerga Lichenol.: 2 (1859).

Protolog: Data lacking.

Protolog type data: An Sandsteinfelsen um Blankenburg im Harz von Hrn. Hampe aufgefunden und mir mitgetheilt. (Die Schimperschen Exemplare aus Abyssinien sind ebenfalls Felsen bewohnend, aber in einer Höhe von 9000-12,000’ gesammelt).

Type locality: Germany, Sachsen-Anhalt, Landkreis Harz, Regenstein wenig nördlich Blankenburg, ca. 300 m, Date unknown but before 1859, E. Hampe, 4131/4, Körber: Lich. Sel. Germ. Exs. 181, usnic acid, salazinic acid (major), constictic acid (minor), protocetraric acid (minor). (L – lectotype; G, M, STR - isolectotype). Lectotypification by Clerc (1987: 487).

Type locality coordinates: 51°48'55"N, 10°57'35"E; 51.815278°, 10.959722°.

Molecular barcode: Data lacking.

Thallus: fruticose, erect relatively small, 3 - 4 - 7 cm long, forming shrubby tufts, + compact, anisotomic-dichotomous near the base, becoming + isotomic towards the extremities, rarely subpendant, 9 - 10 - 15 cm long, the whole thallus being anisotomic-dichotomous. Trunk brownish black or concolorous with the main branches. Annular cracks sparse. Branches I terete, typical irregularly swollen when well developed + articulated. Branches II clearly constricted at their base when well developed, usually with swollen segments. Terminal branches + thick, axils nearly 90°, with numerous soralia; sometimes strongly curved in extreme morphotypes. Papillae sparsely and unevenly distributed, verrucous, with a + rounded apex when well developed, ... (Clerc 1987: 487).

Algae: Data lacking.

Chemistry:
Race I: Usnic acid in the cortex, salazinic acid (major), constictic acid (minor), protocetraric acid (minor) in the medulla. [Lectotype]
Race II: Usnic acid in the cortex, stictic acid group.
Race III: Usnic acid in the cortex, protocetraric acid as main substance in the medulla. [Canary Islands]

Ecology: Corticolous, rarely saxicolous, in oceanic forests.

Molecular data: Genbank

Distribution: Europe, Macaronesia, eastern and western North America, South America, Japan and Australia. Database

Note: In Clerc (2006: 194) the author Georg Ernst Ludwig Hampe (July 5, 1795 – November 23, 1880) is abbreviated as: "G. Hampe" whereas the standardized abbreviation is "Hampe" and the extended correct citation is "Hampe ex Körb.". . The date of the year of description in Clerc (2004: 80) "(1865)" is wrong. The publication "Parerga Lichenologica" by Körber has been published in several parts and the page 2 in the first part was published in 1859.

Usnea dasaea has been described from Madeira in 1881 by Stirton.