mountain sumac vs sumach

mountain sumac and sumach both are nouns.

Word	Noun	Adjective	Verb	Adverb
mountain sumac	Yes	No	No	No
sumach	Yes	No	No	No

As nouns, sumach is a hypernym of mountain sumac; that is, sumach is a word with a broader meaning than mountain sumac:

mountain sumac: common nonpoisonous shrub of eastern North America with compound leaves and green paniculate flowers followed by red berries
sumach: a shrub or tree of the genus Rhus (usually limited to the non-poisonous members of the genus)

Other hypernyms of mountain sumac include shumac, sumac.

mountain sumac (noun)	sumach (noun)
common nonpoisonous shrub of eastern North America with compound leaves and green paniculate flowers followed by red berries	a shrub or tree of the genus Rhus (usually limited to the non-poisonous members of the genus)