Chroogomphus rutilus - Copper Spike

Taxonomy

Phylum: Basidiomycota

Class: Agaricomycetes

Chroogomphus rutilus (synonym: Gomphidius rutilus), a gilled fungus of the order Boletales, is found beneath pine trees, with which it forms ectomycorrhizae. The copper-brown cap of this edible fungus is slimy when wet and dries to a bright glossy copper sheen.

This spike is found throughout Europe and was until recently thought to occur also in the USA; that has been shown to be a different species, now called Chroogomphus ochraceus.

Identification guide

Cap	5 to 12cm in diameter (exceptionally 15cm) the coppery caps of Gomphidius rutilus take on a metallic sheen on sunny days. Occasional specimens flatten fully, sometimes with a sharp umbo, but more often the caps remain convex when mature. In wet weather the caps of this species are viscid, drying with a smooth shiny surface. The pale cap flesh is vinaceous (tinted like red wine).
Gills	Although from its spore characteristics this species is seen to be more closely related to the boletes than to the agaric fungi, it produces its spores via gills rather than pores. The close, thick gills are initially grey-white or dull olive-buff, but they soon take on a dirty purple hue. They are deeply decurrent.
Stem	5 to 12mm in diameter and usually 6 to 12cm tall, the stems are reddish or vinaceous towards the top and yellow towards the base. There is a ring at the apex, where the stem narrows abruptly to the region where the gills are attached. Inside, the stem flesh is firm and solid; like the cap flesh, its colour is vinaceous or pale reddish-brown except near the base, where it becomes chrome yellow.
Spore print	Very dark smoky-olive to black.
Odour/taste	Not distinctive.
Habitat	In grass beneath pines and, less frequently, spruce.
Season	August to November.
Occurrence	Fairly frequent.
Similar species	Gomphidius glutinosus is a much rarer find, also occurring under pines; its cap is grey-violet and its stem is white near the cap and lemon grey towards the base. A glutinous zone at the apex of the stem gradually blackens with age.