Life habit: lichenized (mutualistic with algal photobionts) | lichenicolous (in/on lichens) thallus: crustose (crustaceous) – episubstratal – unspecified | placodioid-crustose, placodioid-foliose thallus: compartimentized – areolate, squamulate [th] upper surface: yellow(ish) (if dull: buff) | red(dish) yellow (orange, orange yellow) [th upper surface]: epruinose [th marginal and upper surface] specific structures: absent [th] morphol substructures (eg areoles, lobes, branches) width [mm]: (low) 0.05 (high) 0.2 [th] morphol substructures (eg areoles, squamules): discontiguous, dispersed (throughout the thallus) | distantly discontiguous [th] morphol substructures (eg areoles, lobes, branches) upper surface: verrucose, warted | bullate [th] lower surface: yellow(ish) (if dull: buff) [th lower surface] specific structures: absent ascomata: absent | present ascoma: apothecial, apothecioid – hymenial ascoma [mm]: (low) 0.3 (high) 1.0 ascoma: sessile, superficial | subpedicellate, substipitate, subpedunculate, substalked | pedicellate, stipitate, pedunculate, stalked [ascm, if apoth] disc, mazaedium: concave | plane, flat, flattened, expanded | subconvex, slightly convex [ascm, if apoth] disc, mazaedium: red(dish) yellow (orange, orange yellow) [ascm, if apoth] disc, mazaedium: epruinose [ascm, if apoth] margin surface; [if perith] periostiolar area, ostiole, involucrellum: red(dish) yellow (orange, orange yellow) [ascm, if apoth] margin excipular photobionts: absent | present | sparse [ascm, if apoth] subhymenial layers, hypothecium; [if perith] basal excipulum: hyaline, colourless [ascm] paraphyses/-oids: present [ascm] paraphyses/-oid cells width [µm]: (low) 2.0 (high) 3.0 [ascm] paraphyses/-oid apical cells width [µm]: (low) 3.0 (high) 6.0 [ascm] epihymenium, epithecium: brown(ish) yellow (ochraceous, ochre) asci: lecanoralean [asc] tholus: thickened [asc] tholus amyloidity (iodine reaction): present [asc] tholus amyloidity pattern: entirely amyloid (= Catillaria-, Teloschistes-types etc) ascospores: (median) 8.0 [asp] shape: ellipsoidal [asp] length [µm]: (low) 11.0 (high) 15.0 [asp] width [µm]: (low) 5.0 (high) 7.5 [asp] septa: absent | present – spore lumen bilocular, polarilocular, plurilocular [asp] septa: transversely septate [asp] transversal septa: (median) 1.0 [asp] pigmentation: hyaline, colourless [asp] perispore, epispore: not apparent primary photobiont: present secondary photobionts (eg in cephalodia): absent primary photobiont: chlorophytaceous – trebouxiaceous, chlorococcoid.

substrate: wood – dead, living | rock – siliceous, siliciferous, acidic | rock, stones, pebbles – unspecified.

Thallus thin, grayish or blackish, granu-lose to disappearing; sometimes with thin whitish hypothallus, K—. Apothecia small, to 0.8 mm broad; margin of same color as thallus, soon disappearing; proper exciple of same color as disk or slightly paler; disk concave to flat and then convex; hypothecium hyaline or yellowish, with oil globules; epihymenium yellow or greenish yellow, granulose, K+ purple; hymenium 60-90 µm, hyaline; paraphyses simple or branching above, tips capitate, 3-5 µm; spores ellipsoid or ovate, polarilocular, 10-16 X 5-8 µm, septum 3-5 µm.

This species grows on the bark of woody plants, old wood, and occasionally on rocks. It is temperate to arctic-boreal, in western North America, ranging south to California and Arizona.

Hansen, Poelt, & S0chting (1987) have treated material of this same sort from Greenland on wood as C. pyracea, stating that it did not appear sensible to them to use the name C. holocarpa, which in their opinion was a temperate zone bark- and wood-inhabiting species. In North America, as the map shows, however, there seems no real hiatus between the temperate and arctic ranges. More study of the C. pyracea group seems needed.