saxifrage vs herbaceous plant

saxifrage and herbaceous plant both are nouns.

Word	Noun	Adjective	Verb	Adverb
saxifrage	Yes	No	No	No
herbaceous plant	Yes	No	No	No

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

saxifrage: any of various plants of the genus Saxifraga
herbaceous plant: 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 herb.

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