The Green Elfcup (Chlorociboria aeruginascens) is far more often noticed by its stain than by its fruit bodies. Fallen branches that have lost their bark are dyed a striking blue-green right through the wood, and once you know the colour you will spot it on woodland walks all year round. The fruit bodies are tiny cups, rarely more than half a centimetre across, in the same verdigris colour on short, off-centre stalks. They are cup-shaped at first and flatten with a wavy edge.
It grows on damp, rotting, bark-free branches of broadleaf trees, especially oak, and the cups appear from August into November.
The stained wood, known as green oak, was prized for decorative inlay, including Victorian Tunbridge ware. A very similar species, Chlorociboria aeruginosa, can only be separated reliably with a microscope. The Green Elfcup is far too small to eat.
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Distribution
Very common
Habitat
On fallen branches of deciduous trees, especially Quercus
Etymology
Chlorociboria is from the Greek chloros, 'green', and the Latin ciborium, 'cup', after the green cups. aeruginascens is Latin for 'becoming verdigris-coloured', after the blue-green stain it gives the wood.
Associates
Quercus
Fruiting Body
Cup-shaped then flattened, goblet-shaped when young, and attached to the wood by a small, off-centre stalk. The margin is wavy and the smooth inner face is blue-green, with a paler, finely felty outer face. It stains the wood it grows on blue-green.
| Colour | |
|---|---|
| Surface | Smooth |
| Width | 0.1 - 0.5 cm |
Flesh
| Odour | Not distinctive |
|---|
Spores
The spores are hyaline (translucent) and allantoid (sausage-shaped). The asci are 8-spored and measure 70x5μm.
| Shape | Allantoid |
|---|---|
| Size | 5.5-8 x 1.5-2 μm |
Classification
- ↳ Phylum: Ascomycota
- ↳ Subphylum: Pezizomycotina
- ↳ Class: Leotiomycetes
- ↳ Subclass: Leotiomycetidae
- ↳ Order: Helotiales
- ↳ Family: Chlorociboriaceae
- ↳ Genus: Chlorociboria
Synonyms
- Chlorociboria aeruginascens (Nyl) Kanouse ex Ramamurthi, Korf & Batra
- Chlorosplenium aeruginascens
- Chlorosplenium aeruginascens (Nyl.) P. Karst.
- Chlorosplenium aeruginosum (Oeder ex With.) de Not.
- Chlorosplenium aeruginosum (Oeder) De Not.
- Dothiora tulasnei (Sacc.) Hohnel
- Helotium aeruginascens
- Helotium aeruginascens (Nyl.) anon. ined.
- Helvella aeruginosa Oeder
- Peziza aeruginascens Nyl.
Reference Sources
T. Læssøe, J. H. Peterson (2019) Fungi of Temperate Europe Vol. 2. Princeton University Press.
R. Phillips (2006) Mushrooms. Macmillan.
Genus Chlorociboria
No other species found in this genus.
