lyre-flower vs herb

lyre-flower and herb both are nouns.

Word	Noun	Adjective	Verb	Adverb
lyre-flower	Yes	No	No	No
herb	Yes	No	No	No

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

lyre-flower: garden plant having deep-pink drooping heart-shaped flowers
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 lyre-flower include herbaceous plant.

lyre-flower (noun)	herb (noun)
garden plant having deep-pink drooping heart-shaped flowers	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