Intro: Ascending to reclining, mat-forming, aquatic perennial floating in mats on the surface of blackwater rivers, sloughs, ditches and ponds, and in very moist soil of ditches and shorelines. Native of tropical America.

Stems: Stems stout, mostly hollow, often red-tinged, hairy at the nodes; will root from the nodes, and in standing water will float on the surface, forming a dense, multi-layer mat with upright branches.

Leaves: Leaves opposite, each pair widely spaced and at right angles to the next, sessile, the leaf base forming a sheath around stem at the node, linear to elliptic, 2--4 in. long, obscurely toothed or entire, smooth.

Inforescence:

Flowers: Flowers in compact heads on long stalks coming from upper leaf nodes, white to off-white, tiny, consisting of 5 1/4-in.-long sepals.

Fruits:

Comments: A serious weed of natural areas.

Height: 2-3 ft.

plant sale text:

bloom table text:

description: Ascending to reclining, mat-forming, aquatic perennial floating in mats on the surface of blackwater rivers, sloughs, ditches and ponds, and in very moist soil of ditches and shorelines. Native of tropical America.

stems: Stems stout, mostly hollow, often red-tinged, hairy at the nodes; will root from the nodes, and in standing water will float on the surface, forming a dense, multi-layer mat with upright branches.

leaves: Leaves opposite, each pair widely spaced and at right angles to the next, sessile, the leaf base forming a sheath around stem at the node, linear to elliptic, 2--4 in. long, obscurely toothed or entire, smooth.

inflorescence:

flowers: Flowers in compact heads on long stalks coming from upper leaf nodes, white to off-white, tiny, consisting of 5 1/4-in.-long sepals.

fruits:

comments: A serious weed of natural areas.

cultural notes:

germination code:

native range: