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Weed Identification

waterthread pondweed



Scientific Name

Potamogeton diversifolius

Other Common Names:

diverse-leaved pondweed
variable pondweed

Synonyms (former Scientific Names):

Potamogeton diversifolius var. multidenticulatus
Potamogeton capillaceus var. atripes
Potamogeton capillaceus


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.

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.

Flower Seed Head

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

Seed Fruit

Roots: Small, thin, rhizomes and fibrous roots. Fruit: An achene that is very small.

Where Found

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.

Life Cycle


Plant Type