Catharanthus roseus vs periwinkle

Catharanthus roseus and periwinkle both are nouns.

Word	Noun	Adjective	Verb	Adverb
Catharanthus roseus	Yes	No	No	No
periwinkle	Yes	No	No	No

As nouns, Catharanthus roseus and periwinkle are synonyms defined as:

Catharanthus roseus and periwinkle: commonly cultivated Old World woody herb having large pinkish to red flowers

Catharanthus roseus (noun)	periwinkle (noun)
commonly cultivated Old World woody herb having large pinkish to red flowers	edible marine gastropod
	small edible marine snail; steamed in wine or baked
	chiefly trailing poisonous plants with blue flowers
	commonly cultivated Old World woody herb having large pinkish to red flowers