Chroogomphus

Chroogomphus is a genus of mushrooms commonly known as pine-spikes or spike-caps based on their shape and because they are often found growing in association with pine trees. The genus is distributed throughout the Northern Hemisphere including North America, the Caribbean, Europe, and Asia.
Taxonomy.
These fungi are members of the family Gomphidiaceae which are agaricoid members of the Boletales (suborder Suillineae). Related to the genus "Gomphidius" (in which they were once classified), "Chroogomphus" are distinguished from "Gomphidius" by their lack of a partial veil.
The genus name is derived from the Greek χρω- chroo-, meaning 'skin' or 'colour', and 'γομφος' "gomphos" meaning 'plug' or 'large wedge-shaped nail'.
Ecology.
Members of this genus have been thought to be ectomycorrhizal with various species of pine, however, there is now evidence that all members of the Gomphidiaceae are parasitic upon other boletes. Specifically, "Chroogomphus" species are thought to be parasitic on various conifer-associated "Suillus" species, with this parasitism often being highly species-specific. In the Pacific Northwest of North America, "C. tomentosus" is found with western hemlock ("Tsuga heterophylla") and Douglas-fir ("Pseudotsuga menziesii"), while "C. helveticus" of Europe is found in conifer forests containing spruce ("Picea" ssp.).
Species.
"Chroogomphus rutilus" (image), found in Europe, is the type species for this genus. It has been the subject of investigation as the source of antibiotics, as well as other potentially useful secondary compounds.
The cap is up to 10 cm in diameter and red-brown in colour. The widely spaced gills are brownish-orange and with black to brownish-yellow spores. The stalk is brownish-yellow and tapers toward the base. The flesh is orange to salmon-coloured and turns violet when chewed.
"Chroogomphus ochraceus" (image) of North America is very similar in habit and appearance to "C. rutilus", and the latter name has often been misapplied to "C. ochraceus".
"Chroogomphus vinicolor" (image), another North American species, is likewise similar to "C. rutilus", although "C. vinicolor" tends to be smaller. The cap color is variable in both species, with "C. vinicolor" being, as its scientific name suggests, more wine-colored while "C. rutilus" is usually more brown. The most distinctive differences between these three species are microscopic. 
Other species within genus "Chroogomphus" include:
Edibility.
"Chroogomphus rutilus", "C. ochraceus", "C. oregonensis", "C. tomentosus", and "C. vinicolor" are edible and may be interchangeable for culinary purposes. They are not, however, regarded as flavorful and possess neither a distinctive taste nor odor. One food writer states about "C. rutilus" and "C. vinicolor": 