What is the smallest flower in the world?

    Water-meal, or Wolffia globosa.

Water-meal is one of the duckweeds in the family Lemnaceae that contains some 38 species of the smallest and simplest flowering plants. The plant itself averages 1/42” long and 1/85” wide or about the size of one candy sprinkle. It can weigh about 1/190,000 of an ounce, equivalent to two grains of table salt. They are very hard to see! Imagine if you tried to fill a thimble with them, it is estimated that you would need some 5000 plants!

Each Wolffia flower consists of a single pistil and stamen; it also produces the world’s smallest fruit, called a utricle. The plant is found in quiet freshwater lakes or marshes with species worldwide. Since the plants have no roots, they can easily float on the surface of the water, where they resemble cornmeal. Water-meal is sometimes used in cold-water aquaria since it is easy to propagate.

Related Web Sites

Duckweed pictures - This will link also to pictures of the fruit. Northern Prairie Wildlife Research Center: Wetland Plants The Smallest Flowering Plants – The Genus Wolffia - Includes several pictures of Wolffia. Wolffia spp. (watermeal) and Wolffiella gladiata (mud midget) - Basic information from Washington State Dept. of Ecology. World’s Smallest Flowering Plant - Information from Wayne P. Armstrong, a professor at Palomar College, who has published a number of articles on Wolffia. On-Line Key to the Genus Wolffia

Further Reading

Alderton, David. Encyclopedia of aquarium & pond fish. New York, Dorling Kindersley, 2005. 400 p. Armstrong, Wayne. P. Duckweeds, California’s smallest wildflowers. Fremontia, v. 10, Oct. 1982: 16-22. Daubs, Edwin Horace. A monograph of Lemnaceae. Urbana, University of Illinois Press, 1965. 118 p. Dore, William G. Wolffia in Canada. Canadian field naturalist, v.71, Jan./Mar. 1957: 10-16. Giesecke, Ernestine. Pond plants. Chicago, Heinemann Library, c1999. 32 p. (Juvenile literature). Lemnaceae/duckweed family. In Crow, Garrett E., and C. Barre Hellquist. Aquatic and wetland plants of northeastern North America. Madison, University of Wisconsin Press, c2000. v. 2, p. 78-84. Saeger, Albert. Flowering of Lemnaceae. Bulletin of the Torrey Botanical Club, v. 56, Oct. 1929: 351-358. Skillicorn, Paul, William Spira, and William Journey. Duckweed aquaculture: a new aquatic farming system for developing countries. Washington, World Bank, c1993. 76 p.

For more print resources...
Search on "Duckweeds," "Aquatic plants," or "Pond plants" in the Library of Congress Online Catalog.

Watermeal - Texas Cooperative Extension site, Dept. of Wildlife & Fisheries Sciences, Texas A & M University.

A bullfrog in duckweed. US Fish and Wildlife Service, Panther National Wildlife Refuge Web site.

Duckweed, watermeal, and filamentous algae cover the water's surface near Maynard, Massachusetts. USGS Massachusetts - Rhode Island Water Science Center Web site.

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