Gymnopilus junonius - Spectacular Rustgill

Taxonomy

Phylum: Basidiomycota

Class: Agaricomycetes

Order: Agaricales

Gymnopilus junonius (synonym: Gymnopilus spectabilis) is a large and colourful wood rotting species that occurs in small groups at the base of dead broad-leaf trees and very occasionally conifers from spring through to early winter. When seen in full sunlight, this mushroom truly earns its common name 'Spectacular'.

This large mushroom is inedible and some authorities state that it is known to be poisonous.

Identification guide

	Cap The cap diameter ranges from 4 to 20cm; initially convex with an in-rolled margin, it eventually flattens but often retains a slight umbo (central raised area). Radial orange or apricot-coloured fibres on a yellow or sienna background give the cap an overall golden appearance, which darkens towards orange brown as the fruitbody ages. The colour of the cap flesh is cream to straw-yellow, and it is firm and quite thick.
	Gills A yellow cortina covers the gills of the immature fruit bodies, breaking and shrivelling to leave fragments around the rim of the cap and around the stipe. The crowded gills are adnate with broad attachment to the stipe. They are straw yellow to buff at first, changing to a bright rusty colour as the spores mature.
	Stem The robust stipe is the same colour as the cap; its surface is fibrous below the ring, which soon gathers spores and turns rusty brown. At the base, the stipe is either bulbous or clavate (club shaped), and the stem is solid with yellow flesh.
Spore print	Rusty brown.
Odour/taste	Faint fruity small; stronger when the flesh is cut. Bitter taste
Habitat	On stumps in deciduous woodland; very occasionally on conifer stumps.
Season	June to November.
Occurrence	Fairly common.
Similar species	Gymnopilus penetrans is yellow-brown, much smaller and lacks a stem ring; it occurs in similar habitat, but unlike Gymnopilus junonius it is more frequently seen on conifer stumps and on sawdust heaps. Phaeolepiota aurea is a rare mushroom with a granulase cap and lower stem; its spores are light yellow-brown.