white madder vs white bedstraw

white madder and white bedstraw both are nouns.

Word	Noun	Adjective	Verb	Adverb
white madder	Yes	No	No	No
white bedstraw	Yes	No	No	No

As nouns, white madder and white bedstraw are synonyms defined as:

white madder and white bedstraw: Eurasian herb with ample panicles of small white flowers; naturalized in North America

Other synonyms of white madder include false baby's breath, Galium mollugo, infant's-breath, wild madder.

white madder (noun)	white bedstraw (noun)
Eurasian herb with ample panicles of small white flowers; naturalized in North America	Eurasian herb with ample panicles of small white flowers; naturalized in North America