Shield dapperling 
Shingled hedgehog 
Shiny Cinnamon Polypore 
Shiny mottlegill 
Silky Pinkgill 
Silky sheath 
Silver leaf 
Silvery Violet Cort 
Singerocybe adirondackensis 
Skullcap dapperling 
Slate Bolete 
Slender Club 
Slender Parasol 
Slender Psathyrella 
Slimy Milkcap 
Slimy spike-cap 
Slippery jack 
Slippery Jill 
Small Funnel-Veil Amanita 
Small Moss Oysterling 
Smoked Oysterling 
Smoky clavaria 
Smoky polypore 
Smoky-brown Clitocybe