Americanized Water Lettuce Gardens Away From Canals, Dams and Paddies

Summary: Americanized water lettuce gardens revel in beneficial, edible and ornamental arums and relegate their weedy relatives to scientific research.

water lettuce (Pistia stratioties) leaves above surface and bountiful root system below water surface; Laie Wetlands, Kihei, south central Maui; Wednesday, Feb. 20, 2008, 10:02:42; image #080220-3062: Forest and Kim Starr, CC BY 2.0 Generic, via Flickr

Americanized water lettuce gardens in aquaria, confined ponds and contained pools always affect dissolved oxygen and light penetration, never alter hydroelectric dam and irrigation canal flows and sometimes attract malaria-vectoring mosquito species.

Temperatures between 71.6 and 86 degrees Fahrenheit (22 and 30 degrees Celsius) beckon the aquatic herb in the Araceae family of arum herbs, shrubs and vines. It carries official, unwelcome weed designations in North America for compromising crop yields, human health and species diversity in rice paddies and in the United States. State legislation demotes the arum family relatives giant duckweed, also called dotted duckmeat, of Australia and southeast Asia and water lettuce to weed status in Texas.

State governments in Alabama, California, Connecticut, Florida and South Carolina expose only water lettuce of Egypt, Sri Lanka and tropical South America to similar weed sanctions.

The seedling's hairless, thin embryonic leaf, called a cotyledon, floats to the surface seven days after its seed's release and five days after the seed's germination.

The first roots grow with the first leaf, whose hairy stoutness gives water lettuce, nicknamed Greek pistra, Nile cabbage, tropical duckweed, water cabbage and watertrough, flotation. Five to 15 gray-green, mature, strong-veined, white-haired, 0.98- to 5.91-inch- (2.5 to 15-centimeter-) long and wide leaves have alternate arrangements that misleadingly hint of basal attachments. They include, near their bases, spongy tissue that induces flotation but that is lost when water lettuce impales itself on mud banks that impede their survival.

Americanized water lettuce gardens jumble ornamental, wild, weedy foliage from related anthurium, caladium, calla lily, philodendron and pothos, duckweed and taro, and jack-in-the-pulpit and skunk cabbage.

Water lettuce, scientifically named Pistia stratiotes (water soldier), keeps mature foliage alongside a fleshy, short, succulent, thick-spiked inflorescence, called a spadix, partly fused to the spathe.

Hairy, large leaf-like, 0.28- to 0.47-inch- (7- to 12-millimeter-) long, 0.19-inch- (5-millimeter-) wide white to pale green bracts, called spathes, with hairless interiors lumber around spadixes. White flowers under 0.19 inches (5 millimeters) across, without petals or sepals, may be six to eight male-flowered whorls around central stalks or solitary female blooms. Feathery, short-branched, 39.37-inch- (100-centimeter-) long roots, 0.08 to 0.28 inches (2 to 7 millimeters) in diameter, and horizontal stems called stolons nourish flowers, foliage and fruits.

Brittle, 23.62-inch- (60-centimeter-) long stems stolons, offer new nodes, with new plant-rooting capabilities, as alternative reproduction means to germinated seeds in June- to September-blooming Americanized water lettuce gardens.

One pistil on a female flower pollinates with two fused stamens on a male flower to produce green berries that each presents four to 15 seeds.

Hairy, light green to brown, oval to oblong, 0.08-inch- (2-millimeter-) long seed germinations quicken between 68 and 77 degrees Fahrenheit (20 and 25 degrees Celsius). Each fleshy fruit, 0.19 to 0.32 inches (5 to 8 millimeters) in diameter, releases some or many seeds of known two-day buoyancies and unknown aquatic viability. Water lettuce, described by Swedish botanist Carl Linnaeus (May 23, 1707-Jan. 10, 1787), survives at 23 degrees Fahrenheit (minus 5 degrees Celsius) as seeds, not plants.

Americanized water lettuce gardens treasure relatives: anthurium, caladium, calla lily, dieffenbachia, philodendron and pothos for beauty; jack-in-the-pulpit for pollinators; taro for starch; and duckweed for research.

Water lettuce plants thrive in wetland environments; Laie Wetlands, Kihei, south central Maui; Wednesday, Jan. 20, 2010, 11:32:19; image #100120-1441: Forest and Kim Starr, CC BY 2.0 Generic, via Flickr

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

water lettuce (Pistia stratioties); Laie Wetlands, Kihei, south central Maui; Wednesday, Feb. 20, 2008, 10:02:42; image #080220-3062: Forest and Kim Starr, CC BY 2.0 Generic, via Flickr @ https://www.flickr.com/photos/starr-environmental/24278154613/;
Forest & Kim Starr, CC BY 4.0 International, via Starr Environmental @ http://www.starrenvironmental.com/images/image/?q=24278154613

Water lettuce plants thrive in wetland environments; Laie Wetlands, Kihei, south central Maui; Wednesday, Jan. 20, 2010, 11:32:19; image #100120-1441: Forest and Kim Starr, CC BY 2.0 Generic, via Flickr @ https://www.flickr.com/photos/starr-environmental/24377312814/; Forest & Kim Starr, CC BY 4.0 International, via Starr Environmental @ http://www.starrenvironmental.com/images/image/?q=24377312814

For further information:

Dickinson, Richard; and Royer, France. 2014. Weeds of North America. Chicago IL; London, England: The University of Chicago Press.

Linnaeus, Carl. 1753. "1. Pistia stratiotes." Species Plantarum, vol. II: 963. Holmiae [Stockholm, Sweden]: Laurentii Salvii [Laurentius Salvius].
Available via Biodiversity Heritage Library @ http://biodiversitylibrary.org/page/358984

"Pistia stratiotes L." Tropicos® > Name Search.
Available @ http://www.tropicos.org/Name/2103622

Weakley, Alan S.; Ludwig, J. Christopher; and Townsend, John F. 2012. Flora of Virginia. Edited by Bland Crowder. Fort Worth TX: BRIT Press, Botanical Research Institute of Texas.