pineapple weed vs rayless chamomile

pineapple weed and rayless chamomile both are nouns.

Word	Noun	Adjective	Verb	Adverb
pineapple weed	Yes	No	No	No
rayless chamomile	Yes	No	No	No

As nouns, pineapple weed and rayless chamomile are synonyms defined as:

pineapple weed and rayless chamomile: annual aromatic weed of Pacific coastal areas (United States and northeastern Asia) having bristle-pointed leaves and rayless yellow flowers

Other synonyms of pineapple weed include Matricaria matricarioides.

pineapple weed (noun)	rayless chamomile (noun)
annual aromatic weed of Pacific coastal areas (United States and northeastern Asia) having bristle-pointed leaves and rayless yellow flowers	annual aromatic weed of Pacific coastal areas (United States and northeastern Asia) having bristle-pointed leaves and rayless yellow flowers