In the Grammatica Latina at the end of Cap. V of LLPSI Pars I, Ørberg has the following examples for singular and plural ablative of each gender:
[A] Masculinum. In horto Iulii. In hortis Italiae.
[B] Femininum. In villa Iulii. In villis Romanis.
[C] Neutrum. In oppido Tusculo. In oppidis Graecis.
In the plural masculine ablative example, why is Italiae used rather than Italis when Graecis is used with the neuter example? I'm assuming Italiae is the nominative plural of the noun, Italia, but Graecis is the ablative plural of the noun Graecus.