subclass Hamamelidae vs genus Hamamelites

subclass Hamamelidae and genus Hamamelites both are nouns.

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

subclass Hamamelidae (noun)	genus Hamamelites (noun)
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	genus of fossil plants having leaves similar to those of the witch hazel