beefsteak mushroom vs brain fungus

beefsteak mushroom

noun

  • Fistulina hepatica (an edible fungus) 

  • Gyromitra esculenta (a potentially fatally poisonous fungus that is a delicacy) 

brain fungus

How often have the words beefsteak mushroom and brain fungus occurred in a corpus of books? (source: Google Ngram Viewer )