"Pereskia subg. Maihuenia Philippi ex F.A.C.Weber, 1898" should be parsed with subg. rank

Pereskia subg. Maihuenia Philippi ex F.A.C.Weber, 1898 means that subgenus Maihuenia is included into genus Pereskia.

We need to add subg. as a rank for non-species "binomials" and then the canonical form for this name should be Maihuenia instead of Pereskia