Bromus inermis vs awnless bromegrass

Bromus inermis and awnless bromegrass both are nouns.

Word	Noun	Adjective	Verb	Adverb
Bromus inermis	Yes	No	No	No
awnless bromegrass	Yes	No	No	No

As nouns, Bromus inermis and awnless bromegrass are synonyms defined as:

Bromus inermis and awnless bromegrass: drought-resistant perennial with awns lacking or very short and long creeping rhizomes; Europe and temperate Asia

Bromus inermis (noun)	awnless bromegrass (noun)
drought-resistant perennial with awns lacking or very short and long creeping rhizomes; Europe and temperate Asia	drought-resistant perennial with awns lacking or very short and long creeping rhizomes; Europe and temperate Asia