order Naiadales vs plant order

order Naiadales and plant order both are nouns.

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

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

order Naiadales (noun)	plant order (noun)
an order of aquatic monocotyledonous herbaceous plants	the order of plants