Zigadenus elegans vs alkali grass

Zigadenus elegans and alkali grass both are nouns.

Word	Noun	Adjective	Verb	Adverb
Zigadenus elegans	Yes	No	No	No
alkali grass	Yes	No	No	No

As nouns, Zigadenus elegans and alkali grass are synonyms defined as:

Zigadenus elegans and alkali grass: plant of western North America having grasslike leaves and greenish-white flowers

Zigadenus elegans (noun)	alkali grass (noun)
plant of western North America having grasslike leaves and greenish-white flowers	plant of western North America having grasslike leaves and greenish-white flowers