Alligator Weed (Alternanthera philoxeroides)

Alternanthera philoxeroides is known by the common names Alligator Weed. It is a water plant although it can grow on dry land. At Fort Yargo State it grows along the lake shore especially in segments 10, 11, and 12. It starts out as a ‘docile’ water plant but gradually grows up over plants on the edge of the lake. In the Fall, rafts of the weed may break loose and float down the lake; they can become quite an obstacle.

Alligator week growing along the lake shore

A small raft of the weed floating loose on the lake. Rafts may be many times this size.

A flower and leaves.

A close up of the flower.

Alternanthera philoxeroides (Alligator Weed) is native to South America, it is considered an invasive plant in the United States. It grows in the southeastern United States, Illinois and California.
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Distribution Map:
- United States Department of Agriculture Plants Database: Alternanthera philoxeroides (Alligatorweed)
- University of North Carolina Herbarium: Alternanthera philoxeroides

Identification resources:
- Southeastern Flora: Alligator Weed (Alternanthera philoxeroides)
- Alabama Plants: Alternanthera philoxeroides

Related posts:
- 2010: Year Of The Wildflower – Wildflower Index