bedstraw vs herb

bedstraw and herb both are nouns.

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

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

bedstraw: any of several plants of the genus Galium
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 bedstraw include herbaceous plant.

bedstraw (noun)	herb (noun)
any of several plants of the genus Galium	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