Not sure. Allison Lake Provincial Park, BC, Canada
Pictures showing different stages of growth over few days. After heavy rain.
Found in parking lot of a marina.
Under hornbeams, cap reddens with KOH - the flesh does not. The pores develop pockets of blue-purple on KOH - and the spore membrane stains blue with KOH see the last photo -63 & 64, black book pg 118
Growing under non-native oaks
In lawn grass, all within 5 feet of planted European Hornbeams (Carpinus betulus).
Third year in this location. Base of a European hornbeam.
Growing in lawn beneath Tilia sp.