Porphyrellus porphyrosporus    (Fr.) E.-J. Gilbert 

common name(s) : Dusky Bolete 

New classification: Basidiomycota/Agaricomycotina/Agaricomycetes/Agaricomycetidae/Boletales/Boletaceae  
Former classification: Basidiomycota/Homobasidiomycetes/Agaricomycetideae/Boletales  

synonyms: Porphyrellus pseudoscaber, Boletus porphyrosporus 
(unconfirmed synonyms: Boletus pseudoscaber, Tylopilus porphyrosporus)  

edibility : discard

potential confusions with  Porphyrellus porphyrosporus toxicity of Porphyrellus porphyrosporus genus Porphyrellus  

The cap is grey-brown to blackish brown, fleshy, firm, hemispherical then convex, flattening in the end. The cap surface is very finely downy, matt and dry, soft to the touch, blackening when touched. The cap margin is thick and incurved.

The stem is massive, full, felty to fibrillose then smooth, easily separated from the cap. It is more or less equal, or narrowing at the top, streaked with longitudinal wrinkles, sometimes erected or arranged in a false network. It is of the same colour as the cap, or is darker. The stem's base is often white because of the white mycelium..

The flesh is quite thick, firm and compact. It is white or slightly greyish, becoming purple grey or green-blue to air before eventually turning blackish, mostly in the cap; its taste is generally not distinctive or unpleasant, somewhat varying; the odour is unpleasant; according to authors: acidic, mouldy or fruity;

The tubes are free, or adnate through a groove, thin, moderately long (8-25mm). They are grey to grey brown then wine purple, turning green when touched, then turning red to black when cut and exposed to air.

The pores are small (up to 1mm), round then a bit angular when mature, concolorous to tubes or darker, turning blue-green when pressed, then purple brown. The spore print is reddish-brown to chocolate brown.

It grows in coniferous or deciduous woods, on sandy pathsides. It is rare in low grounds, and appears more often in the mountains, on a rather acid soil, with spruce, pine, fir, beech.

The fruiting period takes place from June to November.
Dimensions: width of cap approximately 10 cm (between 4 and 17.5 cm)
  height of stem approximately 10 cm (between 4 and 18 cm)
  thickness of stem (at largest section) approximately 20 mm (between 10 and 35 mm)
  spores : 12-20 x 5-7,5 microns, ellipsoid to spindle-shaped

Distinctive features : velvety cap, sometimes with paler patches, darkening when touched; wrinkled stem, concolorous to cap but darker; greyish pore turning reddish-brown, turning blue when pressed; pallid flesh turning red then black when exposed to air

Porphyrellus porphyrosporus is still unreported so far in the forest of Rambouillet, and is quite rare, more generally speaking .

page updated on 14/01/18