silver spruce vs Picea pungens

silver spruce and Picea pungens both are nouns.

Word	Noun	Adjective	Verb	Adverb
silver spruce	Yes	No	No	No
Picea pungens	Yes	No	No	No

As nouns, silver spruce and Picea pungens are synonyms defined as:

silver spruce and Picea pungens: tall spruce with blue-green needles and dense conic crown; older trees become columnar with lower branches sweeping downward

Other synonyms of silver spruce include Colorado blue spruce, Colorado spruce.

silver spruce (noun)	Picea pungens (noun)
tall spruce with blue-green needles and dense conic crown; older trees become columnar with lower branches sweeping downward	tall spruce with blue-green needles and dense conic crown; older trees become columnar with lower branches sweeping downward