in Tuckerman, Edward: The Collected Lichenological Papers 2: 22 (1964).
and in Bryologist 73, 2: 335 (1970).
Basionym: xxx.
Synonym: Index Fungorum
Type: xxx.
Thallus: Much compressed, linear, elongated and pendulous, very much branched; either narrow and somewhat channelled, with teretish tips, or dilated; the longitudinally striate branches often united here and there into a coarse network, and giving forth frequent, lateral, oblong expansions which become foraminous, and at length extended, and densely reticulate-perforate; apothecia mostly marginal, smallish to middling-sized, sub-sessile. Spores ellipsoid, and oblong.
Photobiont:
Chemistry: (+-)-Usnic acid; D-arabitol, no other lichen substances found, by MCT.
Ecology: Trees; California (Menzies.), Noehden l. c. 1800. Northward to Vancouver's Island, J. Macoun.
Molecular data: Genbank
Distribution: Database
Note: The longest specimens seen (a little exceeding a foot) altogether narrow-lobed; from 0.1 mm, at the extremities, to about 1 mm wide. Other specimens run from 1 mm to 15 mm in width, and the widest, perforated expansions exceed 20 mm. Apothecia from 2 mm finally 3-4 mm wide.