羅摩: kagaimo, a vine whose seed pod served as Sukunabikona's boat

羅摩ががいものさや

a kagaimo seed pod

舟ふねは、羅摩ががいもという植物しょくぶつのさやで作つくられていて、乗のっているのは、とても小ちいさな神かみでした。

The boat was made from the pod of a plant called gagaimo, and the one riding in it was a very tiny god.