Potamogeton crispus L.
Curled Pondweed
Entirely submersed; rhizomatous. Stems to 180 cm long, much-branched, ± 4-angled. Leaves sessile, c. 1.5-6-(8) cm × 4-8-(12) mm, linear-oblong, obtuse, conspicuous nerves 3, widely spaced, usually with 2 finer submarginal nerves, margins ± crimped, usually with minute teeth especially towards tip, translucent, occasionally reddish; stipules 3-5 mm long, membranous, delicate and soon deteriorating to fibres. Peduncles 3-5 cm long, terete, often recurved. Spikes 0.5-1 cm long, few-flowered. Achenes to 4 mm long, including prominent curved beak ± = body, dark olive, flattened on sides, keel ± denticulate, lateral angles obscure.
N. Auckland; Gisborne - Lake Waikaremoana; Hawkes Bay; Wellington; abundant. S. Marlborough - near Blenheim; Canterbury - Leithfield Beach, Christchurch, Ikawai. In lakes, ponds, rivers, streams and water races.
(Europe, Asia, Africa, N. America and Australia)
First record: Allan 1940: 304.
First collection: Kitchener Park, Feilding, H. H. Allan, no date [pre-1940] ().
FL. 11-1. FT. 12-3.
Distinct in the submersed habit and oblong, translucent, often reddish leaves with crimped margins, P. crispus alone, or with other submersed or emergent aquatics, often proves a troublesome weed, impeding water flow in slow-moving waters, or forming communities in ± still waters of ponds, dams and bays of lakes. Spread is by seed. and vegetatively from broken pieces of stem: in some occurrences at least, its origin is from surplus material discarded from aquaria or as an escape from deliberately planted stands in garden ponds etc.
