velvet bent grass vs Agrostis canina

velvet bent grass and Agrostis canina both are nouns.

Word	Noun	Adjective	Verb	Adverb
velvet bent grass	Yes	No	No	No
Agrostis canina	Yes	No	No	No

As nouns, velvet bent grass and Agrostis canina are synonyms defined as:

velvet bent grass and Agrostis canina: common grass with slender stems and narrow leaves

Other synonyms of velvet bent grass include brown bent, dog bent, Rhode Island bent, velvet bent.

velvet bent grass (noun)	Agrostis canina (noun)
common grass with slender stems and narrow leaves	common grass with slender stems and narrow leaves