Biatora flavopunctata 
Biatora printzenii 
Bighorn Lichen 
Bilimbia sabuletorum 
Birch Witch's-Broom 
Birch Woodwart 
Black bulgar 
Black Knot 
Black Morel 
Black Sooty Mold 
Black Tar Spot 
Black Truffle 
Black-Eye Lichen 
Bleach cup 
Blistered Cup 
Blue Jellyskin 
Blushing Scale 
Bolete eater 
Boreal button lichen 
Boreal Oakmoss 
Botryosphaeria dothidea 
Bottlebrush Frost Lichen 
Bracted sulphur lichen 
Branched pixie-cup lichen