sumac vs sumach

sumac and sumach both are nouns.

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

As nouns, sumac and sumach are synonyms defined as:

sumac and sumach: a shrub or tree of the genus Rhus (usually limited to the non-poisonous members of the genus)

Other synonyms of sumac include shumac.

sumac (noun)	sumach (noun)
a shrub or tree of the genus Rhus (usually limited to the non-poisonous members of the genus)	a shrub or tree of the genus Rhus (usually limited to the non-poisonous members of the genus)
wood of a sumac