class Dicotyledonae vs subclass Rosidae

class Dicotyledonae and subclass Rosidae both are nouns.

Word	Noun	Adjective	Verb	Adverb
class Dicotyledonae	Yes	No	No	No
subclass Rosidae	Yes	No	No	No

class Dicotyledonae (noun)	subclass Rosidae (noun)
comprising seed plants that produce an embryo with paired cotyledons and net-veined leaves; divided into six (not always well distinguished) subclasses (or superorders): Magnoliidae and Hamamelidae (considered primitive), Caryophyllidae (an early and distinctive offshoot), and three more or less advanced groups: Dilleniidae, Rosidae, Asteridae	a group of trees and shrubs and herbs mostly with polypetalous flowers; contains 108 families including Rosaceae, Crassulaceae, Myrtaceae, Melastomaceae, Euphorbiaceae, Umbelliferae