Hypomyces chrysospermus 

Hypomyces chrysospermus on boletes6028

Hypomyces chrysospermus Tul. & C. Tul. 

is a parasitic ascomycete that infects particular species in the Boletales including boletes, leccinums, Paxillus and Rhizopogon. It passes through color changes starting out white and ending up a bright egg-yoke yellow. Inedible. It is in the Hypocreaceae family in the Hypocreales order of the ascomycota. 

Hypomyces chrysospermus1152

Hypomyces chrysospermus on boletes