culm vs molasses cane

culm

noun
  • the stem of a plant, especially of grass or sedge 

  • anthracite, especially when found in small masses 

  • waste coal, used as a poor quality fuel; slack. 

molasses cane

noun
  • A plant, commonly sugar cane, maize/corn, sorghum (maize or milo), or other another fructose-producing grass plant (of the family Gramineae) used for production of cane syrup or molasses. 

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