Cirsium helenioides vs Cirsium heterophylum

Cirsium helenioides and Cirsium heterophylum both are nouns.

Word	Noun	Adjective	Verb	Adverb
Cirsium helenioides	Yes	No	No	No
Cirsium heterophylum	Yes	No	No	No

As nouns, Cirsium helenioides and Cirsium heterophylum are synonyms defined as:

Cirsium helenioides and Cirsium heterophylum: perennial stoloniferous thistle of northern Europe with lanceolate basal leaves and usually solitary heads of reddish-purple flowers

Other synonyms of Cirsium helenioides include melancholy thistle.

Cirsium helenioides (noun)	Cirsium heterophylum (noun)
perennial stoloniferous thistle of northern Europe with lanceolate basal leaves and usually solitary heads of reddish-purple flowers	perennial stoloniferous thistle of northern Europe with lanceolate basal leaves and usually solitary heads of reddish-purple flowers