Silvery Violet Cort 
Singerocybe adirondackensis 
Skullcap dapperling 
Slender Club 
Slender Parasol 
Slender Psathyrella 
Small Funnel-Veil Amanita 
Small Moss Oysterling 
Smoked Oysterling 
Smoky clavaria 
Smoky-brown Clitocybe 
Smoky-Gilled Hypholoma 
Snakeskin Grisette 
Snowy Waxcap 
Soap-scented toadstool 
Soft puffball 
Soft Slipper 
Spectacular Rustgill 
Spiny Puffball 
Splitgill Mushroom 
Spotted cort 
Spotted Toughshank 
Spruce Feather 
Steel blue rozites