Onion Earthball 
Onion-stalk Parasol 
Onnia subtriquetra 
Ophiocordyceps buquetii 
Ophiocordyceps dipterigena 
Ophiocordyceps unilateralis 
Orange Birch Bolete 
Orange bonnet 
Orange Coral 
Orange Earth Tongue 
Orange Gilled Waxcap 
Orange Jelly Spot 
Orange Lichen 
Orange milkcap 
Orange Moss Agaric 
Orange mycena 
Orange Oak Bolete 
Orange oyster 
Orange peel fungus 
Orange Pinwheel 
Orange Polypore 
Orange Polypore Mold 
Orange pore fungus 
Orange pore fungus