Variable-leaf Pondweed

Potamogeton diversifolius

Alternate names
Waterthread Pondweed

Weed Description
A perennial with both floating and submersed leaves that are elliptic to oval in outline. This weed is a common aquatic weed of ponds, streams, and lakes that is found throughout the United States.

Leaves
Both floating and submersed leaves occur on the same plants. Floating leaves are elliptic to oval in outline, reaching 2 inches in length and ranging from 10 to 20 mm in width. Floating leaves usually have 7 to 11 distinct veins. Submersed leaves are arranged alternately along the stem and are usually smaller than the floating leaves. Submersed leaves have 3 veins, only 1 of which is usually noticeable. Submersed leaves have stipules at the base of the leaf petiole that forms a sheath around the stem.

Flowers
Flowers are spikes that occur on short flower stalks (peduncles) and arise just above the water surface.

Fruit
An achene that is very small.

Roots
Small, thin, rhizomes and fibrous roots.

Identifying Characteristics
The relatively small elliptical floating and submersed leaves and distinctively veined leaves of this plant helps to distinguish it from most other pondweeds.

Office of Programs

University of Missouri

Variable-leaf Pondweed

Potamogeton diversifolius