scarlet pimpernel vs red pimpernel

scarlet pimpernel and red pimpernel both are nouns.

Word	Noun	Adjective	Verb	Adverb
scarlet pimpernel	Yes	No	No	No
red pimpernel	Yes	No	No	No

As nouns, scarlet pimpernel and red pimpernel are synonyms defined as:

scarlet pimpernel and red pimpernel: herb with scarlet or white or purple blossoms that close at approach of rainy weather

Other synonyms of scarlet pimpernel include Anagallis arvensis, poor man's weatherglass.

scarlet pimpernel (noun)	red pimpernel (noun)
herb with scarlet or white or purple blossoms that close at approach of rainy weather	herb with scarlet or white or purple blossoms that close at approach of rainy weather