Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2004. Lichen Flora of the Greater Sonoran Desert Region. Vol 2.

Thallus: small, thin, uniform, continuous, smooth to granulose, definite and limited by a dark brown black prothalline line, or thallus diffuse or indistinct surface: smooth, white or pale green, pale yellowish green to yellowish gray Apothecia: numerous, scattered, +round, sessile, constricted at base, 0.2-0.7(-1) mm in diam. disc: black, plane or slightly concave, greenish pruinose when young, finally epruinose exciple: with an erect proper margin, rather thin, mostly entire, becoming somewhat rugulose or wavy to dentate; "epihymenium": granulose, green-black hymenium: hyaline, 45-70 µm tall, I+ pale red, K/I+ blue; paraphysoids: branching or simple, free, up to 1.5 µm wide below, with tips thickened (3-4 µm wide) and dark green, with dark brown cap formed in the inner part of the cell wall; subhymenium: hyaline, 25-40 µm thick, I+ slightly blue/red or pale red, K/I+ blue; hypothecium: broad, black, continuous with the broad black exciple asci: clavate, 35-45 x 10-12 µm at maturity, 8-spored ascospores: hyaline, (2-)3(-4)-septate, straight or slightly curved, ovoid to oblong-ellipsoid, finger-shaped or broadly fusiform, often somewhat widened at one end, 11-15(-17) x 3-5 µm; walls: slightly thickened at septa Pycnidia: immersed or semi-immersed in the thallus, 100-120 µm tall, 90-100 µm wide conidia: hyaline, 3-5 x 1-1.5 µm Spot tests: thallus K+ yellow, C-, KC-, P- Secondary metabolites: none detected. Substrate and ecology: on trees and old wood of conifers (Picea, Abies, Cedrus, Taxus, etc.) or deciduous trees (Acer, Populus, Fraxinus, Quercus, etc.), often in coniferous or mixed forest; sometimes near the ocean World distribution: warm to cold temperate areas of the Northern Hemisphere in Europe, Asia; and North America (mainly in the East) Sonoran distribution: southern California. Notes: Reports of Lecanactis premnea (Ach.) Arnold (= Cresponea premnea) from California, by Tuckerman (1872), Hasse (1898), Merrill (1923), and Fink (1935) are apparently based on C. chloroconia, although C. premnea v. saxicola (Leight.) Egea & Torrente does occur in Alabama and Missouri. Cresponea premnea differs from