Non-Native to Chesapeake Bay; non-invasive in tidal waters, invasive in
- Family - Potamogetonaceae
- Distribution - Curly pondweed grows in fresh non-tidal
to slightly brackish tidal waters. Curly pondweed is thought to have been
introduced from Europe in mid-1800's; today it has worldwide distribution and is
widely distributed in streams, rivers and reservoirs of the Chesapeake Bay.
- Recognition - Leaves are 3 cm to 10 cm (1 ¼ in to 4 in)
long, broad, linear and finely toothed, with undulated (curly) margins. Leaves
are arranged alternately or slightly opposite on flattened, branched stems.
Roots and rhizomes are shallow, and not as extensive as in other
bay grasses. Vegetative
buds sprout in the fall and the winter form of the plant develops with
blue-green leaves that are more flattened. In spring, the spring/summer form
appears with reddish-brown leaves that are wider and curlier. Flowering occurs
in late spring or early summer and the plants begin to die-off in midsummer
after the vegetative buds are produced. The buds remain dormant until fall, when
the cycle is repeated.
- Ecological Significance - Curly pondweed is an introduced
species that is widespread throughout the U.S. Curly pondweed has a three-stage
life cycle and distinctly different winter and summer forms. Curly pondweed can
be particularly invasive when it occurs in lakes and reservoirs (non-tidal
- Similar Species - Curly pondweed may resemble young shoots of
redhead grass (Potamogeton perfoliatus).
- Reproduction - Plants reproduce through extension of rhizomes,
development of burr-like asexual structures near stem tips, and by seed
development from flowers that float at water surface atop spikes. The curly
pondweed life-cycle has a three-stages: winter form, spring/summer form, and
dormant vegetative (asexual) bud.
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