genus Hamamelidanthum vs subclass Hamamelidae

genus Hamamelidanthum and subclass Hamamelidae both are nouns.

Word	Noun	Adjective	Verb	Adverb
genus Hamamelidanthum	Yes	No	No	No
subclass Hamamelidae	Yes	No	No	No

genus Hamamelidanthum (noun)	subclass Hamamelidae (noun)
genus of fossil plants of the Oligocene having flowers resembling those of the witch hazel; found in Baltic region	a group of chiefly woody plants considered among the most primitive of angiosperms; perianth poorly developed or lacking; flowers often unisexual and often in catkins and often wind pollinated; contains 23 families including the Betulaceae and Fagaceae (includes the Amentiferae); sometimes classified as a superorder