order Myricales vs plant order

order Myricales and plant order both are nouns.

Word	Noun	Adjective	Verb	Adverb
order Myricales	Yes	No	No	No
plant order	Yes	No	No	No

As nouns, plant order is a hypernym of order Myricales; that is, plant order is a word with a broader meaning than order Myricales:

order Myricales (noun)	plant order (noun)
coextensive with the family Myricaceae	the order of plants