genus Cucurbita vs Cucurbita maxima

genus Cucurbita and Cucurbita maxima both are nouns.

Word	Noun	Adjective	Verb	Adverb
genus Cucurbita	Yes	No	No	No
Cucurbita maxima	Yes	No	No	No

genus Cucurbita (noun)	Cucurbita maxima (noun)
type genus of the Cucurbitaceae	any of several winter squash plants producing large greyish-green football-shaped fruit with a rough warty rind
	plant bearing buff-colored squash having somewhat bottle-shaped fruit with fine-textured edible flesh and a smooth thin rind