Gomphidius

Gomphidius is a genus of mushrooms, commonly known as spike-caps, that are members of the Boletales (suborder Suillineae), or pored fungi. They appear to have gill-like structures which resemble those of agarics, however the similarity is superficial only. The best-known member is the slimy spike-cap ("Gomphidius glutinosus"). The genus has a widespread distribution, especially in north temperate areas, and contains 10 species.
Taxonomy.
Elias Magnus Fries initially described the genus as "Agaricus" subgenus "Gomphus" in 1821, before renaming it "Gomphidius" in 1825.
The genus gives its name to the family Gomphidiaceae. Despite being agaricoid (bearing gills) the genus (and family) belong to the Boletales (suborder Suillineae). The related genus "Chroogomphus" (whose species were once classified in "Gomphidius"), is distinguished by the lack of a partial veil.
The genus name is derived from the Greek 'γομφος' "gomphos" meaning 'plug' or 'large wedge-shaped nail'.
Fries did not designate a type species, but "G. glutinosus" was later designated the lectotype as it was the first species listed.
Miller subdivided the genus into three sections, section "Microsporus", typified by small spores, with "G. oregonensis" as the type, section "Roseogomphus", typified by large spores and pink cap, with "G. subroseus" as its type, and section "Gomphidius".
Miller published a molecular analysis of the Gomphidiaceae in 2003, though material was not available from all taxa. The results showed "G. flavipes" and "G. pseudoflavipes" were sister taxa and their lineage was sister to a Japan-provenance material of "G. roseus". "G. glutinosus" and "G. oregonensis" were sister taxa with "G. smithii", "G. subroseus" and "G. nigricans" as progressively earlier offshoots. "G. maculatus" diverged from the ancestor of these eight species, and "Gomphidius borealis" may be an early offshoot that is basal to the split between "Chroogomphus" and "Gomphidius". Miller suggested that the gasteroid species "Gomphogaster leucosarx" may lie within "Gomphidius" but did not analyse that taxon genetically.
Description.
The members of the genus have pink- to purple-, grey- or brown-tinted caps that have a sticky surface and a varnished appearance when dry. They have white gills.
Distribution and habitat.
The genus occurs in coniferous forests throughout North America, Eurasia and North Africa. "Gomphidius" species associate with members of the subfamilies Piceoideae ("Picea"), Laricoideae ("Larix" and "Pseudotsuga") and Abietoideae ("Abies" and "Tsuga") within the Pinaceae.