Picea mariana vs black spruce

Picea mariana and black spruce both are nouns.

Word	Noun	Adjective	Verb	Adverb
Picea mariana	Yes	No	No	No
black spruce	Yes	No	No	No

As nouns, Picea mariana and black spruce are synonyms defined as:

Picea mariana and black spruce: small spruce of boggy areas of northeastern North America having spreading branches with dense foliage; inferior wood

Other synonyms of Picea mariana include spruce pine.

Picea mariana (noun)	black spruce (noun)
small spruce of boggy areas of northeastern North America having spreading branches with dense foliage; inferior wood	small spruce of boggy areas of northeastern North America having spreading branches with dense foliage; inferior wood