Chlorociboria aeruginascens - Green Elfcup

Taxonomy

Class: Leotiomycetes

Order: Helotiales

Family: Insertae sedis (placement uncertain)

The green-stained wood that is evidence of Green Elfcup, Chlorociboria aeruginascens, is a common sight, but the fruit bodies are seen only infrequently. This winter fungus is sometimes referred to as Green Cup fungus.

Wood infected with this fungus has long been used in such decorative woodworking as Tunbridge ware. In Italy the practice dates at least as far back as the 14th century, when it was used in 'intarsia', an inlaying process rather similar to marquetry.

In Britain there are just two species in the genus Chlorciboria, the other being Chlorociboria aeruginosa. Both result in green staining, and the fruitbodies of the two species cannot be differentiated on macroscopic characteristics, but at 5 to 7 x 1 to 2µm the spores of Chlorciboria aeruginascens are significantly smaller than those of Chlorciboria aeruginosa (9 to14 x 2 to 4µm).

Identification guide

	Fruitbody Initially shaped like a goblet with a very short stem, the fruit bodies flatten with age and develop wavy edges. Individual fruit bodies are 0.5 to 1cm in diameter and usually less than 1cm tall. The upper, fertile surface is bright green and smooth, while the underside of the cup and the stipe are felty and pale blue-green, darkening with age. Another scientific name for this species is Chlorosplenium aeruginascens.
Spore print	White.
Odour/taste	Not distinctive.
Habitat	On bark-free dead wood, particularly oak, beech and hazel.
Season	The green stain is visible all the year round, but fruit bodies occur infrequently and mainly in autumn.
Occurrence	Fruiting very infrequently.
Similar species	No other common cup fungus is blue-green, although several dark species, including Bulgaria inquinans, occur in similar habitats.