Which preposition to use with duckweed

from Occurrences 2%

Ours now, the duckweed from the stream we bear, And cook to use with other viands rare.

in Occurrences 1%

But his face was a face of such happiness that, had you seen it, you would have understood indeed how that he had died happy, never knowing that cool and streaming silver for the duckweed in the pond.

Which preposition to use with  duckweed