Bromus inermis vs brome

Bromus inermis and brome both are nouns.

Word	Noun	Adjective	Verb	Adverb
Bromus inermis	Yes	No	No	No
brome	Yes	No	No	No

As nouns, brome is a hypernym of Bromus inermis; that is, brome is a word with a broader meaning than Bromus inermis:

Bromus inermis: drought-resistant perennial with awns lacking or very short and long creeping rhizomes; Europe and temperate Asia
brome: any of various woodland and meadow grasses of the genus Bromus; native to temperate regions

Other hypernyms of Bromus inermis include bromegrass.

Bromus inermis (noun)	brome (noun)
drought-resistant perennial with awns lacking or very short and long creeping rhizomes; Europe and temperate Asia	any of various woodland and meadow grasses of the genus Bromus; native to temperate regions