duckweed

But the farm had fallen on evil days at the hands of Paddy Magragh, and the reservoir was choked with cresses and duckweed.

Waterlilies and duckweed are not the chief part of this floating mass.

There is a large pond in the midst of the garden, covered with duckweed, and full of beautiful gold and silver fish of many kinds.

The river is rising fast, and bringing down large quantities of aquatic grass, duckweed, &c.