rock plant vs flora

rock plant and flora both are nouns.

Word	Noun	Adjective	Verb	Adverb
rock plant	Yes	No	No	No
flora	Yes	No	No	No

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

rock plant: plant that grows on or among rocks or is suitable for a rock garden
flora: (botany) a living organism lacking the power of locomotion

Other hypernyms of rock plant include plant, plant life.

rock plant (noun)	flora (noun)
plant that grows on or among rocks or is suitable for a rock garden	(botany) a living organism lacking the power of locomotion
	all the plant life in a particular region or period