helianthus vs sunflower

helianthus and sunflower both are nouns.

Word	Noun	Adjective	Verb	Adverb
helianthus	Yes	No	No	No
sunflower	Yes	No	No	No

As nouns, helianthus and sunflower are synonyms defined as:

helianthus and sunflower: any plant of the genus Helianthus having large flower heads with dark disk florets and showy yellow rays

helianthus (noun)	sunflower (noun)
any plant of the genus Helianthus having large flower heads with dark disk florets and showy yellow rays	any plant of the genus Helianthus having large flower heads with dark disk florets and showy yellow rays