Porphyrellus porphyrosporus - Dusky Bolete

Taxonomy

Phylum: Basidiomycota

Class: Agaricomycetes

With purple-brown cap and stipe, Porphyrellus porphyrosporus is a rather dull and sombre-looking bolete and not at all easy to spot, despite its large size. This summer and autumn species occurs under pines, often in dark woodland settings that add to the difficulty of spotting mushrooms with dark brown caps against a dark brown background. This is a rare mushroom and the only member of its genus that occurs in Europe. Its cap, stem and spore colours make it very easy to identify.

Identification Guide

Cap	This sombre mushroom has a dark brown cap with a noticeably paler margin. Initially convex, caps expand and sometimes become irregularly lobed. 6 to 15cm in diameter when fully expanded, the caps have soft buff flesh with a vinaceous tinge.
Tubes and Pores	The tubes and pores are greyish-yellow at first (as in the youngish specimen shown here) but, as the fruiting body begins releasing spores, the pores turn brown. When cut or bruised, the tubes turn blue-green.
Stem	1 to 3cm in diameter and 5 to 12cm tall, the stems of this species are tobacco brown and slightly velvety to the touch when young, becoming smooth as the fruiting body matures. The stem flesh is buff, turning slightly blue-green near the apex when cut.
Spore print	Vinaceous-brown.
Odour/taste	Unpleasant sour taste and odour.
Habitat	Under deciduous trees and in conifer forests.
Season	July to September.
Occurrence	Rare.
Similar species	The Bay Bolete, Boletus badius, is similar but with a shiny cap when fully developed; its tubes turn more blue when bruised.