Zigadenus venenosus vs Zigadenus venenosus gramineus

Zigadenus venenosus and Zigadenus venenosus gramineus both are nouns.

Word	Noun	Adjective	Verb	Adverb
Zigadenus venenosus	Yes	No	No	No
Zigadenus venenosus gramineus	Yes	No	No	No

As nouns, Zigadenus venenosus and Zigadenus venenosus gramineus are synonyms defined as:

Zigadenus venenosus and Zigadenus venenosus gramineus: plant of western North America to Mexico; poisonous especially to grazing animals

Other synonyms of Zigadenus venenosus include grassy death camas.

Zigadenus venenosus (noun)	Zigadenus venenosus gramineus (noun)
plant of western North America to Mexico; poisonous especially to grazing animals	plant of western North America to Mexico; poisonous especially to grazing animals