Xanthoconium is a genus of bolete fungi in the family Boletaceae. It was circumscribed by mycologist Rolf Singer in 1944, who included Boletus affinis and what was then known as Gyroporus stramineus as the type species. These two species were part of the "strange group of species described by Murrill and Snell as white-spored Gyropori, and separated by the latter under the new generic name Leucogyroporus." C.B. Wolfe described three species from the United States in 1987: X. chattoogaense, Xanthoconium montaltoense, and X. montanum., the nomenclatural database Index Fungorum list seven species in Xanthoconium.
The concept of Xanthoconium has been not fully described using molecular phylogenetic analysis, but it is clearly a distinct genus, apart from Boletus. However, Xanthoconium separans was found to be more closely related to Boletus Sensu stricto than to Xanthoconium.
| Image | Scientific name | Taxon author | Year | Distribution |
|---|---|---|---|---|
| Xanthoconium affine | (Peck) Singer | 1944 | hardwood forests east of the Rocky Mountains, and in Mexico | |
| Xanthoconium chattoogaense | Wolfe | 1987 | Known only from the type locality, along a tributary of the Chattooga River in North Carolina. | |
| Xanthoconium fusciceps | N.K. Zeng, Zhi Q. Liang & S. Jiang | 2017 | China | |
| Xanthoconium montaltoense | Wolfe | 1987 | Found in south-central Pennsylvania. | |
| Xanthoconium montanum | Wolfe | 1987 | Found in Macon County, North Carolina, in Nantahala National Forest. | |
| Xanthoconium porophyllum | G. Wu & Zhu L. Yang | 2016 | China | |
| Xanthoconium purpureum | Snell & E.A.Dick | 1962 | eastern North America | |
| Xanthoconium separans | (Peck) Halling & Both | 1998 | South Eastern United States | |
| Xanthoconium sinense | G. Wu, Y.Y. Cui & Zhu L. Yang | 2016 | China | |
| Xanthoconium stramineum | (Murrill) Singer | 1944 | eastern North America | |