lemon lily vs Hemerocallis flava

lemon lily and Hemerocallis flava both are nouns.

Word	Noun	Adjective	Verb	Adverb
lemon lily	Yes	No	No	No
Hemerocallis flava	Yes	No	No	No

As nouns, lemon lily and Hemerocallis flava are synonyms defined as:

Other synonyms of lemon lily include Hemerocallis lilio-asphodelus.

lemon lily (noun)	Hemerocallis flava (noun)
a day lily with yellow flowers	a day lily with yellow flowers