sessile joyweed USDA PLANTS Symbol: ALSE4
U.S. Nativity: Exotic
Habit: Aquatic Forbs/Herbs
Alternanthera sessilis (L.) R. Br. ex DC.

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Taxonomic Rank: Magnoliopsida: Caryophyllales: Amaranthaceae
Native Range: Temp. & trop. Asia (GRIN);

Identification, Biology, Control and Management Resources

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Seed(s); Our descriptive literature says that A. sessilis is unique for the genus in that the tepals (perianth segments) are shorter than (rarely barely as long as) the heart-shaped, one-seeded fruit. This picture shows tepals which exceed the fruit in length.
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Fruit(s); Three fruits with perianth still attached. FNW taxon.
Julia Scher, USDA APHIS PPQ,
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Seed(s); Face view of two seeds, with hilum at bottom. Embryo peripheral, visible on surface under testa, encircling perisperm. FNW taxon.
Julia Scher, USDA APHIS PPQ,
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EDDMapS Distribution:
This map is incomplete and is based only on current site and county level reports made by experts and records obtained from USDA Plants Database. For more information, visit

State(s) Where Reported invasive.
Based on state level agency and organization lists of invasive plants from WeedUS database.

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U.S. National Parks where reported invasive:
Haleakala National Park (Hawaii)

Invasive Listing Sources:
Georgia Exotic Pest Plant Council
Jil M. Swearingen, Survey of invasive plants occurring on National Park Service lands, 2000-2007
Tennessee Exotic Pest Plant Council