Alnus rhombifolia vs alder

Alnus rhombifolia and alder both are nouns.

Word	Noun	Adjective	Verb	Adverb
Alnus rhombifolia	Yes	No	No	No
alder	Yes	No	No	No

As nouns, alder is a hypernym of Alnus rhombifolia; that is, alder is a word with a broader meaning than Alnus rhombifolia:

Alnus rhombifolia: tree of western United States
alder: north temperate shrubs or trees having toothed leaves and conelike fruit; bark is used in tanning and dyeing and the wood is rot-resistant

Other hypernyms of Alnus rhombifolia include alder tree.

Alnus rhombifolia (noun)	alder (noun)
tree of western United States	north temperate shrubs or trees having toothed leaves and conelike fruit; bark is used in tanning and dyeing and the wood is rot-resistant
	wood of any of various alder trees; resistant to underwater rot; used for bridges etc