Spiraea vs rosid dicot genus

Spiraea and rosid dicot genus both are nouns.

Word	Noun	Adjective	Verb	Adverb
Spiraea	Yes	No	No	No
rosid dicot genus	Yes	No	No	No

As nouns, rosid dicot genus is a hypernym of Spiraea; that is, rosid dicot genus is a word with a broader meaning than Spiraea:

Spiraea (noun)	rosid dicot genus (noun)
a dicotyledonous genus of the family Rosaceae	a genus of dicotyledonous plants