Species & plants
Duckweed
Also known as: Lemna minor
Duckweed (Lemna minor) is the smallest flowering plant most people will encounter — tiny oval green fronds 2–5 mm across with a single visible root underneath. Native to North America but invasive in behavior on nutrient-loaded ponds, where coverage can double in 48 hours. Frequently confused with watermeal (Wolffia), which is even smaller, has no root, and is much harder to remove. Both indicate excess phosphorus in the water column.
Related terms
- WatermealThe smallest flowering plant in the world; rootless, under 1 mm, looks like green grit on the water surface.
- Phosphorus loadingThe rate of phosphorus inputs to a water body; the limiting nutrient for most freshwater algae blooms.
- Doubling timeThe time required for an aquatic plant population to double in biomass under given conditions.