ague weed vs stiff gentian

ague weed and stiff gentian both are nouns.

Word	Noun	Adjective	Verb	Adverb
ague weed	Yes	No	No	No
stiff gentian	Yes	No	No	No

As nouns, ague weed and stiff gentian are synonyms defined as:

ague weed and stiff gentian: gentian of eastern North America having clusters of bristly blue flowers

ague weed (noun)	stiff gentian (noun)
gentian of eastern North America having clusters of bristly blue flowers	gentian of eastern North America having clusters of bristly blue flowers