The stunning blue-green Chlorociboria cups can be stalked or unstalked and are 2 - 6 mm in diameter. Most of the time you don't see the actual fruiting bodies but the brilliantly green-stained wood of hardwoods, including poplar, aspen, oak and ash. Woodworkers call this wood "green rot" or "green stain." Chlorociboria species are not considered "true" wood decay fungi as are the white-rot and brown-rot Basidiomycetes [click here for more explanation about how basidiomycetes decay lignin and cellulose], but these ascomycetes may be soft-rot fungi that can cause small amounts of erosion in the wood cell walls. It is also possible that they do not degrade the cell wall directly but colonize wood decayed by other fungi earlier in the decay process.