Maximilian's sunflower vs Helianthus maximilianii

Maximilian's sunflower and Helianthus maximilianii both are nouns.

Word	Noun	Adjective	Verb	Adverb
Maximilian's sunflower	Yes	No	No	No
Helianthus maximilianii	Yes	No	No	No

As nouns, Maximilian's sunflower and Helianthus maximilianii are synonyms defined as:

Maximilian's sunflower and Helianthus maximilianii: tall perennial of central United States to Canada having golden-yellow flowers

Maximilian's sunflower (noun)	Helianthus maximilianii (noun)
tall perennial of central United States to Canada having golden-yellow flowers	tall perennial of central United States to Canada having golden-yellow flowers