Scientific name: Potamogeton crispus L.
Common name: Curled Pondweed
Description
Habit: Aquatic perennials. Stems compressed. Hybrids are rather frequent in this genus.
Leaves: Leaves mostly alternate, some opposite, submerged, subtending inflorescences, all with membranous sheath or stipules; submerged leaves linear-oblong, 7-15mm wide, obtuse margin strongly waved and finely toothed, with teeth easily visible to the naked eye, 3-5(7)-veined; stipules small, membranous, soon decaying.
Flowers: In spikes or heads; spike small and rather lax, with about 8 flowers; peduncle slender, about 50mm long; usually borne above the water-surface; perianth of 4 free, greenish segments; carpels usually 4, free; stamens 4, anthers stalkless, attached to the base of the adjoining perianth-segment.
Fruits: Drupes or achenes, 1 or more present, 4-6mm, including the beak, the beak equalling or longer than the body of the carpel, with thick pericarp, soft on outside but with bony inner layer.
Habitat: Still or slowly moving water.
Distribution: Very frequent in most districts.
Native status: Native
Of conservation interest: No