Japanese name: アオウキクサ（青浮草） Scientific name:Lemna aoukikusa subsp. aoukikusa
[Overview]
A small annual that floats on the surface of water in paddy fields, ponds and similar places.
The fronds, in which leaf and stem are not distinguished, float on the water and produce roots.
Usually 3–5 fronds gather to form a colony.
The fronds are obovate to elliptic, 0.3–0.6 cm long and 0.2–0.3 cm wide, with entire margins and three visible veins; they are thin, and the base is asymmetrical.
The fronds are yellowish green to green and never tinged with purple.
A single root grows from the underside of the frond; it is slightly wavy with a pointed tip, and the sheath surrounding the root base is winged.
The flowers are very small, and an inflorescence consisting of 1 female flower and 2 male flowers is borne on the edge of the frond.
The seeds are oblong, with 18–26 longitudinal ribs and 44–82 transverse ribs.
In autumn the fronds die, and the plant overwinters as seed.
