CHAPTER III. Nomenclature of taxa according to their rank
SECTION 1. Names of taxa above the rank of family
Article 17
Automatically typified names of orders or suborders are to end in -ales (but not -virales) and -ineae, respectively (see Art. 16.3 and 32.2).
Names intended as names of orders, but published with their rank denoted by a term such as “cohors”, “nixus”, “alliance”, or “Reihe” instead of “order”, are treated as having been published as names of orders.
Recommendation 17A
A new name should not be published for an order for which a name already exists that is based on the same type as the name of an included a family.