Mexican poppy vs devil's fig

Mexican poppy and devil's fig both are nouns.

Word	Noun	Adjective	Verb	Adverb
Mexican poppy	Yes	No	No	No
devil's fig	Yes	No	No	No

As nouns, devil's fig is a hypernym of Mexican poppy; that is, devil's fig is a word with a broader meaning than Mexican poppy:

Mexican poppy: annual herb with prickly stems and large yellow flowers; southern United States to West Indies and Mexico
devil's fig: any plant of the genus Argemone having large white or yellow flowers and prickly leaves and stems and pods; chiefly of tropical America

Other hypernyms of Mexican poppy include argemone, prickly poppy, white thistle.

Mexican poppy (noun)	devil's fig (noun)
annual herb with prickly stems and large yellow flowers; southern United States to West Indies and Mexico	any plant of the genus Argemone having large white or yellow flowers and prickly leaves and stems and pods; chiefly of tropical America