Using the plant oenothera lamarckiana, or evening primrose, hugo de vries discovered stable new variants in multiple generations when the plants were bred. what term did he coin when referring to these dramatic variants?

Mutation

Explanation:

De Vries, following his discovery of stable new variants in several generations when the Oenothera lamarckiana is planted, coined the word mutation. In his observation, the original plant occasionally bears offspring that vary significantly in their phenotypic features  such as  leaf shape, which remains stable and can be passed on to the next generation. He referred to these dramatic variants as mutation.  

De Vries is said to be the father of Mutation. He is best known for propounding the Mutation Theory.