white cedar vs southern white cedar

white cedar and southern white cedar both are nouns.

Word	Noun	Adjective	Verb	Adverb
white cedar	Yes	No	No	No
southern white cedar	Yes	No	No	No

As nouns, white cedar and southern white cedar are synonyms defined as:

white cedar and southern white cedar: slow-growing medium-sized cedar of east coast of the United States; resembles American arborvitae

Other synonyms of white cedar include Atlantic white cedar, Chamaecyparis thyoides, coast white cedar, white cypress.

white cedar (noun)	southern white cedar (noun)
slow-growing medium-sized cedar of east coast of the United States; resembles American arborvitae	slow-growing medium-sized cedar of east coast of the United States; resembles American arborvitae
small evergreen of eastern North America having tiny scalelike leaves on flattened branchlets