Paspalum distichum vs knotgrass

Paspalum distichum and knotgrass both are nouns.

Word	Noun	Adjective	Verb	Adverb
Paspalum distichum	Yes	No	No	No
knotgrass	Yes	No	No	No

As nouns, Paspalum distichum and knotgrass are synonyms defined as:

Paspalum distichum and knotgrass: low-growing weedy grass with spikelets along the leaf stems

Paspalum distichum (noun)	knotgrass (noun)
low-growing weedy grass with spikelets along the leaf stems	low-growing weedy grass with spikelets along the leaf stems