Walnut mycena 
Waxy laccaria 
Weeping Widow 
Western flat-top Agaricus 
Western giant puffball 
Western grisette 
Western Panther 
Whetstone's Amidella 
White American star-footed Amanita 
White Coral Fungus 
White dommecap 
White Dunce Cap 
Wine-colored Agaricus 
Winter Oysterling 
Winter Stalk-Puffball 
Witch's hat 
Wood blewit 
Wood mushroom 
Wood Pinkgill 
Wood Woolyfoot 
Woodland inkcap 
Woolly Bird's Nest Fungus 
Wrinkled Fieldcap 
Wrinkled peach