Stubby-stalk 
Stump fairy helmet mushroom 
Subalpine waxycap 
Suillus caerulescens 
Suillus cavipes 
Suillus collinitus 
Suillus cothurnatus 
Suillus grevillei 
Suillus hirtellus 
Suillus mediterraneensis 
Suillus ponderosus 
Suillus punctatipes 
Suillus sibiricus 
Suillus tomentosus 
Suillus tridentinus 
Sulphur knight 
Sulphur tuft 
Summer Bolete 
Sunset Spindles 
Swamp beacon 
Swarming Spine 
Sweetgum Leaf Spot 
Switchgrass Rust Fungus 
Syzygites megalocarpus