black sally vs black gum

black sally and black gum both are nouns.

Word	Noun	Adjective	Verb	Adverb
black sally	Yes	No	No	No
black gum	Yes	No	No	No

As nouns, black sally and black gum are synonyms defined as:

black sally and black gum: a small mallee with rough dark-colored bark toward the butt; yields a red eucalyptus kino gum

Other synonyms of black sally include black mallee, Eucalytus stellulata.

black sally (noun)	black gum (noun)
a small mallee with rough dark-colored bark toward the butt; yields a red eucalyptus kino gum	columnar tree of eastern North America having horizontal limbs and small leaves that emerge late in spring and have brilliant color in early fall
	a small mallee with rough dark-colored bark toward the butt; yields a red eucalyptus kino gum