Return to Scale View
About

How big is Duckweed?

2 millimeters!

View History Report
Duckweed

Duckweeds are tiny flowering plants that float on ponds and other still fresh water. Each plant is a small, leaf-like body called a frond, and some kinds have roots hanging below. The explorer shows one frond 2 millimeters (0.08 inches) long, within the range of common duckweed, Lemna minor, whose fronds are 1–8 millimeters long.

Size

A duckweed has no true stem. Its frond is only a few cells thick, and air spaces inside it keep it afloat. Across all the duckweeds, fronds range from 1 to 15 millimeters in length or width.

Common duckweed has egg-shaped fronds 1–8 millimeters long and 0.5–6.2 millimeters wide. Its single root can grow up to 15 centimeters (6 inches) long. The explorer's 2-millimeter frond sits toward the small end of the species' range.

Size comparisons

  • About 13 fronds 2 millimeters long, laid end to end, would span one inch (2.54 centimeters).
  • A 2-millimeter frond is nearly three times as long as a 0.7-millimeter mechanical pencil lead is wide.
  • Four grains of table salt 0.5 millimeters across would fit along its length.
  • A root 15 centimeters long is 75 times the length of a 2-millimeter frond.
  • Columbian water-meal, one of the smallest flowering plants, is 0.5–1.4 millimeters long, so a 2-millimeter frond is 1.4–4 times its length.

How duckweed grows

Duckweeds can flower and make seeds, but they grow mainly by budding: new daughter fronds grow out of one or two pouches in the mother frond. The fronds stay joined for a while, forming small colonies that spread across the water.

As of 2025, duckweeds are the fastest-growing flowering plants known. A 2018 study listed a doubling time of about one day for Wolffia microscopica, the fastest-growing species. Under good conditions, duckweed can cover a pond within a few days. Because the plants take up nutrients and pollutants from the water as they grow, they can also be used to clean polluted water.

The smallest flowering plants

The smallest duckweeds belong to the genus Wolffia, called water-meal. Columbian water-meal, Wolffia columbiana, has no roots. As of 2026, the botanical guide Go Botany describes it as generally considered the smallest flowering plant on Earth.

In Thailand, another species, Wolffia globosa, is sold in vegetable markets under local names meaning "water eggs". It is eaten in salads, omelets and curries. Water-meal plants are 20–30% protein by dry weight.

Sources

ابعاد جهان > Duckweed
Pencil Lead
People use pencil lead a lot. Oh, by the way, this is mechanical pencil lead. On another note, the largest pencil contained 2,000 kilograms of graphite. That's about three times heavier than a human! And by human I mean the heaviest human ever.
Amoeba
Amoebae are unicellular, which means there is only one cell. Some amoebae can grow to an incredible 700 micrometers, which is almost an entire millimeter.
Grain of Salt
Salt is a compound made of a reactive metal and a toxic gas. Everyone knows that. Also, do not eat too much salt, or else you could die. Eating one thousandth of your body weight all at once will usually do the trick.
Ant
You probably don't like ants. That's too bad. 15-25% of all land animals are ants! Whoa! That's a lot of ants! For every person on Earth, there are over one million ants!
Sleet
Sleet, which falls from the sky, is made of ice pellets. That ball to the left is an ice pellet. Sleet is similar to snow, but it's much denser. You also may have noticed that sleet is significantly smaller than hail.
Grain of Rice
A lot of people on our beautiful world eat rice. If you eat one bowl of rice per day, you will eat around 300 million grains of rice in your lifetime. That is also approximately the population of the United States!

Discussion