saxifrage vs herb

saxifrage and herb both are nouns.

Word	Noun	Adjective	Verb	Adverb
saxifrage	Yes	No	No	No
herb	Yes	No	No	No

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

saxifrage: any of various plants of the genus Saxifraga
herb: a plant lacking a permanent woody stem; many are flowering garden plants or potherbs; some having medicinal properties; some are pests

Other hypernyms of saxifrage include herbaceous plant.

saxifrage (noun)	herb (noun)
any of various plants of the genus Saxifraga	aromatic potherb used in cookery for its savory qualities
	a plant lacking a permanent woody stem; many are flowering garden plants or potherbs; some having medicinal properties; some are pests