Rhus glabra vs shumac

Rhus glabra and shumac both are nouns.

Word	Noun	Adjective	Verb	Adverb
Rhus glabra	Yes	No	No	No
shumac	Yes	No	No	No

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

Rhus glabra: common nonpoisonous shrub of eastern North America with waxy 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 Rhus glabra include sumac, sumach.

Rhus glabra (noun)	shumac (noun)
common nonpoisonous shrub of eastern North America with waxy 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)