Terana coerulea

Scientific name: Terana coerulea (Lam.) Pers.
Derivation of name: The specific epithet coerulea
means "blue."  
Synonyms: Byssus coerulea Lam.; Pulcherricium
coeruleum (Lam.) Parmasto; Corticium coeruleum
(Lam.) Fr.  
Common name(s):  Cobalt crust, velvet blue spread.
Phylum:   Basidiomycota
Order:   Polyporales
Family:  Phanerochaetaceae
Occurrence on wood substrate: Saprobic; on dead
hardwoods, usually on the underside of logs and the lower
side of limbs and branches on the ground in warm, damp
forests; summer through fall.   
Dimensions: Variable in size, typically 3-10 cm wide and
2-6 mm thick.
Description: The velvety blue patches of this fungus are
crustlike with several patches often grouped together. The
margins are typically paler in color. When moist, the
crusts are velvety or waxy but become brittle when dry.
Comments: Compared to most crust fungi, the cobalt blue
color of velvet blue spread makes this fungus easily
identifiable without microscopic examination. Very few
fungi of any shape are blue, thereby granting cobalt crust
membership in a very exclusive set of fungi. The genus
Terana is monotypic meaning it contains the single species
Terana coerulea. The common spelling variation Terana
caerulea is not recognized by Index Fungorum.

Figure 1. The unmistakable velvet blue spread on a dead
hardwood branch. The specimen was found in October in
southeast PA. Photo © George Morrison.

Figure 2. A closer look at Terana coerulea on the branch
in Figure 1. Photo © George Morrison.

Figure 3. The margins of this species are flat against the
wood and paler in color. Photo © George Morrison.