genus Hackelia vs plant genus

genus Hackelia and plant genus both are nouns.

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

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

genus Hackelia (noun)	plant genus (noun)
stickweed; beggar's lice	a genus of plants