Exidia pithya

Exidia pithya is a species of fungus in the family Auriculariaceae. Basidiocarps (fruit bodies) are gelatinous, black, and button-shaped at first, later coalescing and drying to form tar-like patches. The species grows on dead branches of conifers in continental Europe.

Taxonomy
The species was originally found growing on pine in Germany and was described in 1805 by the German mycologists Johannes Baptista von Albertini and Lewis David de Schweinitz.

Description
Exidia pithya forms grey-black to brown-black, gelatinous fruit bodies that are button-shaped at first, coalescing with age and forming effused patches up to 20 cm long. The upper, spore-bearing surface is normally smooth, becoming slightly furrowed, occasionally with a few scattered pegs or warts. The spore print is white.

Microscopic characters
The microscopic characters are typical of the genus Exidia. The basidia are ellipsoid and septate. The spores are cylindrical to weakly allantoid (sausage-shaped), 11 to 15 by 4 to 5 μm.

Similar species
Fruit bodies of Exidia glandulosa and E. nigricans are similarly coloured, but occur on broad leaved trees. Fruit bodies of E. saccharina and E. umbrinella occur on conifers, but are brown to orange-brown.

Habitat and distribution
Exidia pithya is a wood-rotting species, typically found on dead branches. It was originally described from pine (Pinus species), but is more common on spruce (Picea species) and less common on fir and larch (Abies and Larix species). It is widely distributed throughout continental Europe from Scandinavia to Turkey, but is absent from the British Isles.