Thallus: fruticose, caespitose, sparingly branched branches: with blades up to 4 cm long surface: pale green, smooth or gently wrinkled, usually with abundant black maculae, sorediate soredia: white or gray, borne in soralia that are primarily terminal medulla: medulla white and cottony, well-formed, without distinct chondroid strands but medullary hyphae adhese in groups of +three ("medulla hyphae in short bundles and in ropelike cords," Spjut, 1996) Apothecia: rare, subterminal when present, c. 1 mm in diam. disc: pale, similar to N. ceruchis, flat or gently concave asci: clavate, 8-spored ascospores: hyaline, 1-septate, fusiform, straight to gently curved, rarely strongly curved, 10-14 x 4 µm (12-20 µm in length fide Spjut, 1996) Pycnidia: black; immersed conidia: straight, rod-shaped Spot tests: either all negative or K+ yellow to orange or deep red or P+ orange for salazinic or norstictic acids (fide Spjut, 1996) present Secondary metabolites: zeorin, (-)-16α-hydroxykaurane, usnic acid, +salazinic acid, and, fide Spjut (1996), with four combinations of secondary metabolites as follows: (1) +salazinic acid, (2) norstictic acid (3) T3 triterpene and other terpenoids, and (4) T3 triterpene and salazinic acid triterpenes, zeorin, (-)-16α-hydroxykaurane. Substrate and ecology: on bark, rarely occurring on rock World distribution: central Chile and Pacific Coast of North America from southern Alaska to Washington south to Baja California Sur Sonoran distribution: southern California in the Channel Islands to the Vizcaíno Peninsula and Cedros Island, Baja California Sur. Notes: Niebla cephalota is readily identified as the only sorediate species in the genus. It is caespitose when large and almost stubby when small, but the characteristic large white soralia in the terminal sections of the blades make it easily recognized. Apothecia are rare and are subterminal to terminal when they do occur. The blade surface is smooth or gently wrinkled, often maculate, and the black pycnidia are uncommon. In herbaria, conspicuous, cottony, and web like exudates aggregate around the soralia, often covering the entire plant in old collections. It is chemically variable, with salazinic acid present in many specimens from the San Quintín area, and a number of combinations of secondary metabolites occur throughout its distribution.