Pluteus DB15314    "The Undescribed White Scaly Pluteus"      All Collections: Sierra Nevada, Spring

This is one of the frequently encountered, lignicolous, white Pluteus species that typically gets identified as Pluteus petasatus. Even a cursory look microscopically reveals that the name is misapplied. From all literature that I have consulted this one appears to be an undescribed species -- the spores are much larger and the hyphae of the pileipellis are ubiquitously clamped.

Spores quite variable, up to 12 long   

Clamped septa of the pileipellis -- very frequent, approximately every 1 out of 5.