black sumac vs shumac

black sumac and shumac both are nouns.

Word	Noun	Adjective	Verb	Adverb
black sumac	Yes	No	No	No
shumac	Yes	No	No	No

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

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

Other hypernyms of black sumac include sumac, sumach.

black sumac (noun)	shumac (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)