wild lupine vs old-maid's bonnet

wild lupine and old-maid's bonnet both are nouns.

Word	Noun	Adjective	Verb	Adverb
wild lupine	Yes	No	No	No
old-maid's bonnet	Yes	No	No	No

As nouns, wild lupine and old-maid's bonnet are synonyms defined as:

wild lupine and old-maid's bonnet: stout perennial of eastern and central North America having palmate leaves and showy racemose blue flowers

Other synonyms of wild lupine include Indian beet, Lupinus perennis, sundial lupine.

wild lupine (noun)	old-maid's bonnet (noun)
stout perennial of eastern and central North America having palmate leaves and showy racemose blue flowers	stout perennial of eastern and central North America having palmate leaves and showy racemose blue flowers