Hercules'-club vs Hercules'-clubs

Hercules'-club and Hercules'-clubs both are nouns.

Word	Noun	Adjective	Verb	Adverb
Hercules'-club	Yes	No	No	No
Hercules'-clubs	Yes	No	No	No

As nouns, Hercules'-club and Hercules'-clubs are synonyms defined as:

Hercules'-club and Hercules'-clubs: densely spiny ornamental of southeastern United States and West Indies

Other synonyms of Hercules'-club include Hercules-club, Zanthoxylum clava-herculis.

Hercules'-club (noun)	Hercules'-clubs (noun)
densely spiny ornamental of southeastern United States and West Indies	densely spiny ornamental of southeastern United States and West Indies
small deciduous clump-forming tree or shrub of eastern United States