genus Geranium vs plant genus

genus Geranium and plant genus both are nouns.

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

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

genus Geranium (noun)	plant genus (noun)
genus of mostly North American geraniums: cranesbills	a genus of plants