WordNet (r) 3.0 (2006):

winter mushroom
    n 1: an edible agaric that is available in early spring or late
         fall when few other mushrooms are; has a viscid smooth
         orange to brown cap and a velvety stalk that turns black in
         maturity and pallid gills; often occur in clusters [syn:
         winter mushroom, Flammulina velutipes]