noun
Asian watermeal; Wolffia globosa
A tiny aquatic plant, one of the smallest flowering plants. Used in biology and ecology contexts.
ミジンコウキクサは水面に浮かぶ非常に小さな植物だ。
Asian watermeal is a very small plant that floats on the water surface.
この池にはミジンコウキクサがたくさん繁殖している。
A lot of Asian watermeal is growing in this pond.
ウキクサ (duckweed) is a more general term for floating aquatic plants, while ミジンコウキクサ refers specifically to Wolffia globosa, a much smaller species.
The name combines 微塵子 (みじんこ, water flea) and 浮草 (うきくさ, duckweed), referring to its tiny size and floating habit. The exact derivation is uncertain, but it is a descriptive compound.