silky elm vs angiospermous tree

silky elm and angiospermous tree both are nouns.

Word	Noun	Adjective	Verb	Adverb
silky elm	Yes	No	No	No
angiospermous tree	Yes	No	No	No

As nouns, angiospermous tree is a hypernym of silky elm; that is, angiospermous tree is a word with a broader meaning than silky elm:

Other hypernyms of silky elm include flowering tree.

silky elm (noun)	angiospermous tree (noun)
large tree of Australasia	any tree having seeds and ovules contained in the ovary