A monographic treatment with keys and photographs. The spp. are distr. among 3 subgenera, Chroogomphus, Laricogomphus and Myxogomphus, of which the 1st and 3d have 2 sects. each. 13 spp. are admitted. G. roseus does not occur in the W. Hemisphere; G. rhodoxanthus and G. foliiporus belong to the genus Phylloporus. G. ochraceus is divided into ssp. typicus, ssp. muscigenus, and ssp. superiorensis (G. s. Kauffm. and Smith). All spp. are ssp. descr. macro- and microscopically, including data on the anatomy of the hymenophoral trama and the veil as well as on the wall of the cystidia and their incrustation. In most cases, the macrochemical reactions of the fresh specimens are indicated. The habitat, as far as mycorrhizal relationships are concerned, has been studied with special emphasis on the section or series to which the accompanying pines belong as well as on the accompanying mycorrhiza-forming Suilloideae (boletes). Style and arrangement are those of "North American Flora.".