Pediocactus knowltonii vs Knowlton's cactus

Pediocactus knowltonii and Knowlton's cactus both are nouns.

Word	Noun	Adjective	Verb	Adverb
Pediocactus knowltonii	Yes	No	No	No
Knowlton's cactus	Yes	No	No	No

As nouns, Pediocactus knowltonii and Knowlton's cactus are synonyms defined as:

Pediocactus knowltonii and Knowlton's cactus: small clustering cactus of southwestern United States; a threatened species

Pediocactus knowltonii (noun)	Knowlton's cactus (noun)
small clustering cactus of southwestern United States; a threatened species	small clustering cactus of southwestern United States; a threatened species