Quercus kelloggii vs oak

Quercus kelloggii and oak both are nouns.

Word	Noun	Adjective	Verb	Adverb
Quercus kelloggii	Yes	No	No	No
oak	Yes	No	No	No

As nouns, oak is a hypernym of Quercus kelloggii; that is, oak is a word with a broader meaning than Quercus kelloggii:

Quercus kelloggii: large deciduous tree of the Pacific coast having deeply parted bristle-tipped leaves
oak: a deciduous tree of the genus Quercus; has acorns and lobed leaves

Other hypernyms of Quercus kelloggii include oak tree.

Quercus kelloggii (noun)	oak (noun)
large deciduous tree of the Pacific coast having deeply parted bristle-tipped leaves	a deciduous tree of the genus Quercus; has acorns and lobed leaves
	the hard durable wood of any oak; used especially for furniture and flooring