dead-man's-fingers vs Xylaria polymorpha

dead-man's-fingers and Xylaria polymorpha both are nouns.

Word	Noun	Adjective	Verb	Adverb
dead-man's-fingers	Yes	No	No	No
Xylaria polymorpha	Yes	No	No	No

As nouns, dead-man's-fingers and Xylaria polymorpha are synonyms defined as:

dead-man's-fingers and Xylaria polymorpha: the fruiting bodies of the fungi of the genus Xylaria

Other synonyms of dead-man's-fingers include dead-men's-fingers.

dead-man's-fingers (noun)	Xylaria polymorpha (noun)
the fruiting bodies of the fungi of the genus Xylaria	the fruiting bodies of the fungi of the genus Xylaria