Onosmodium vs plant genus

Onosmodium and plant genus both are nouns.

Word	Noun	Adjective	Verb	Adverb
Onosmodium	Yes	No	No	No
plant genus	Yes	No	No	No

As nouns, plant genus is a hypernym of Onosmodium; that is, plant genus is a word with a broader meaning than Onosmodium:

Onosmodium: a genus of North American perennial herbs of the family Boraginaceae
plant genus: a genus of plants

Onosmodium (noun)	plant genus (noun)
a genus of North American perennial herbs of the family Boraginaceae	a genus of plants