Raoulia australis vs herb

Raoulia australis and herb both are nouns.

Word	Noun	Adjective	Verb	Adverb
Raoulia australis	Yes	No	No	No
herb	Yes	No	No	No

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

Raoulia australis: perennial prostrate mat-forming herb with hoary woolly foliage
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 Raoulia australis include herbaceous plant.

Raoulia australis (noun)	herb (noun)
perennial prostrate mat-forming herb with hoary woolly foliage	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