Synonym(s): Achyranthes sessilis (L.) Desf. ex Steud. Alternanthera glabra Moq., Gomphrena sessilis L.
Duration and Habit: Annual, Perennial Forb/Herb
A low lying and sprawling herbaceous perennial, A. sessilis can range across the ground from 20-60 meters. Roots will often grow from nodes. Leaves are glabrous and grow directly from the stem. Leaf shapes are typically elliptical, oblong and oblanceolate and can range from 1.12-2.2 cm in length. Inflorescences grow at the axil and are sessile. The inflorescence is composed of small, white, ovate to lanceolate tepals. Fruits are small bladder-like structures containing one lenticular shaped seed. Seeds are roughly 0.9-1.1 mm long. (Flora of North America:Alternanthera sessilis)
Ecological Threat: Covering large areas and very adaptable, A. sessilis can reduce crop yield and infest wetland areas. Plants can block irrigation pipes and canals. (Alternanthera sessilis- Fact Sheet, 2014) It has noxious, prohibited, or quarantine weed status in AL, AR, CA, FL, MA, MN, NC, OR, SC and VT.
Biology & Spread: Can grow in dry areas but can also live partially submerged in water. Seeds are the main reproduction strategy but roots can form at nodes.
History: Likely escaped from aquatic gardens or aquaria.
U.S. Habitat: A. sessilis can survive in both wetlands and agricultural areas and is highly adaptable.
U.S. Nativity: Introduced to U.S.
Native Origin: Southern Asia
U.S. Present: AL, AR, FL, GA, LA, MD, MI, SC, TX
Distribution: Southeastern U.S.
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