morel vs truffle

morel

noun
  • Any of several edible mushrooms, especially the common morel or yellow morel. 

  • Any of several fungi in the genus Morchella, the upper part of which is covered with a reticulated and pitted hymenium. 

truffle

noun
  • Any of various edible fungi, of the genus Tuber, that grow in the soil in southern Europe; the earthnut. 

How often have the words morel and truffle occurred in a corpus of books? (source: Google Ngram Viewer )