Domain: Eukarya
Kingdom: Fungi
Phylum: Ascomycota
Class: Leotiomycetes
Order: Helotiales
Family: Helotiaceae
Genus: Chlorociboria

Small green cups fruiting on decayed wood which is stained green by the fungus.

It has smaller spores than C. aeruginosa.
Some authors claim that the two species can be separated on the color of the flesh (orangish to yellowish for Chlorociboria aeruginosa and blue-green for Chlorociboria aeruginascens. Most authors indicate microscopy is needed.

Widely distributed in North America and Europe.

On decorticated wood of broadleaf and conifer trees.

Chlorociboria aeruginosa

The stained wood has been used in making valuable products such as Tunbridge ware and furniture inlay.

http://botit.botany.wisc.edu/toms_fungi/jul2008.html
http://www.mushroomexpert.com/...
http://www.speciesfungorum.org/...

Chlorociboria aeruginascens (Nyl.) Kanouse ex C.S. Ramamurthi, Korf & L.R. Batra, Mycologia 49(6): 858 (1958) ¹⁹⁵⁷ subsp. aeruginascens

Synonymy:
Chlorociboria aeruginascens (Nyl.) Kanouse, Mycologia 39(6): 641 (1947)
Chlorociboria aeruginascens (Nyl.) Kanouse ex C.S. Ramamurthi, Korf & L.R. Batra, Mycologia 49(6): 858 (1958) ¹⁹⁵⁷
Chlorosplenium aeruginascens (Nyl.) P. Karst., Bidr. Känn. Finl. Nat. Folk 19: 103 (1871)
Peziza aeruginascens Nyl.,: 42 (1869)