dulse vs kombu

dulse

noun
  • A seaweed of a reddish-brown color (Palmaria palmata) which is sometimes eaten, as in Scotland. 

kombu

noun
  • Edible kelp (“a type of brown seaweed”) (from the class Phaeophyceae) used in East Asian cuisine. 

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