おうすぎごけだったら
大杉苔だったら
ō sugigokedattara

Noun
Da Copula

The "-tara" conditional form ("if/when…") of おおすぎごけ

1. If it were Ōsugi-toke…; If Ōsugi-toke were…

Tara Conditional
Usually Written in Kana