non-flowering plant vs flora

non-flowering plant and flora both are nouns.

Word	Noun	Adjective	Verb	Adverb
non-flowering plant	Yes	No	No	No
flora	Yes	No	No	No

As nouns, flora is a hypernym of non-flowering plant; that is, flora is a word with a broader meaning than non-flowering plant:

Other hypernyms of non-flowering plant include plant, plant life.

non-flowering plant (noun)	flora (noun)
a plant that does not bear flowers	(botany) a living organism lacking the power of locomotion
	all the plant life in a particular region or period