Asclepias perennis, also known as aquatic milkweed or white swamp milkweed (not to be confused with swamp milkweed; Asclepias incarnata), is a North American species of milkweed that is found throughout the Coastal Plain from eastern Texas to southern South Carolina, northward along the Mississippi River, and into the Ohio Valley of Illinois, Indiana, and Kentucky. There seems to be a few disjunct populations in Arkansas, Texas, and Indiana.

A similar species, Asclepias texana, looks morphologically similar but differs by a very divided distribution (central and western Texas), growing in dry rocky soils, and having more broadly ovate leaves.

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