bur reed vs herb

bur reed and herb both are nouns.

Word	Noun	Adjective	Verb	Adverb
bur reed	Yes	No	No	No
herb	Yes	No	No	No

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

bur reed: marsh plant having elongated linear leaves and round prickly fruit
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 bur reed include herbaceous plant.

bur reed (noun)	herb (noun)
marsh plant having elongated linear leaves and round prickly fruit	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