Cobalt Crust

Appearance

"Terana caerulea" is resupinate, meaning the fruiting body lies on the surface of the substrate, with the hymenium exposed to the outside. The fruiting body is 2–6 mm thick. It is dark blue with a paler margin, with a velvety or waxy texture when moist, but crusty and brittle when dry. The fruiting body is firmly attached to its growing surface except at the edges. In nature, the fungus surface is typically found pointing downward, which helps facilitate spore dispersal. It usually grows on dead deciduous wood, often ash and hazel. The spore print is white. Spores are ellipsoidal, smooth, thin-walled, hyaline or pale blue, with dimensions of 7–12 by 4–7 µm. The four-spored basidia are club-shaped, hyaline or blue, with dimensions of 40–60 by 5–7 µm.

Naming

This species, which for a member of the corticioid fungi is relatively easy to identify, was first described in 1779 by Jean-Baptiste Lamarck, who is best known for proposing an early theory of evolution. Lamarck used the name "Byssus caerulea", and various other designations were subsequently employed, until in 1828 Fries classified it as "Thelephora violascens" variety "coerulea". According to rule 13.1.d. of the International Code of Botanical Nomenclature, valid publication of fungal names is treated as beginning with Fries's publication of "Systema Mycologicum" in 1821 and following years. This means that the correct species name is "coerulea", not "caerulea". Both names are found frequently in the literature. Strangely enough, Lamarck's name "Byssus" has now come to be applied to a plant genus - a fundamentally different organism.

In 1763 Michel Adanson had devised the genus name "Terana" for similar crust fungi and in 1891 Otto Kuntze included "coerulea" in that genus to create the modern name. Apart from this, the genus "Pulcherricium" was proposed by Parmasto in 1968 for this one species and the name "Pulcherricium caerulea/coerulea" is sometimes seen, but the designation "Terana" is better established.

Distribution

The cobalt crust has a worldwide distribution in warmer climates, and has been reported from Asia, Africa, New Zealand, North America, the Canary Islands, Europe, Taiwan, Thailand, and Turkey.