Perennial Duckweed

Lemna turionifera has fronds that are 1-4 mm long and 0.8-3.5 mm wide, typically 1-1 1/2 times as long as wide. The fronds are somewhat shiny on the upper surface with distinct papules along the nerves. Three nerves are present, and the largest air spaces are rarely wider than 0.3 mm. The rootcap is mostly rounded, sometimes pointed. Occasionally, rootless turions appear at the end of the vegetation period, which sink to the bottom of the water for the cold season. Flowers and fruits are rare, with the ovary containing one ovule, a style 0.15-0.20 mm long, and a fruit 0.5-0.6 mm long and 0.6-0.8 mm wide. Seeds are 0.5-0.8 mm long, about 0.5 mm thick, whitish, with 30-60 indistinct ribs.