angiospermous tree vs class Angiospermae

angiospermous tree and class Angiospermae both are nouns.

Word	Noun	Adjective	Verb	Adverb
angiospermous tree	Yes	No	No	No
class Angiospermae	Yes	No	No	No

angiospermous tree (noun)	class Angiospermae (noun)
any tree having seeds and ovules contained in the ovary	comprising flowering plants that produce seeds enclosed in an ovary; in some systems considered a class (Angiospermae) and in others a division (Magnoliophyta or Anthophyta)