western saxifrage vs rockfoil

western saxifrage and rockfoil both are nouns.

Word	Noun	Adjective	Verb	Adverb
western saxifrage	Yes	No	No	No
rockfoil	Yes	No	No	No

As nouns, rockfoil is a hypernym of western saxifrage; that is, rockfoil is a word with a broader meaning than western saxifrage:

western saxifrage: saxifrage having loose clusters of white flowers on hairy stems growing from a cluster of basal leaves; moist slopes of western North America
rockfoil: any of various plants of the genus Saxifraga

Other hypernyms of western saxifrage include breakstone, saxifrage.

western saxifrage (noun)	rockfoil (noun)
saxifrage having loose clusters of white flowers on hairy stems growing from a cluster of basal leaves; moist slopes of western North America	any of various plants of the genus Saxifraga