Scientific name: Potamogeton natans L.
Common name: Broad-leaved Pondweed
Description
Habit: Aquatic perennials. Hybrids are rather frequent in this genus.
Leaves: Leaves mostly alternate, some opposite, submerged or floating (rarely aerial on marshy ground), subtending inflorescences, all with membranous sheath or stipules; submerged leaves absent or reduced to stalks less than 5mm wide, opaque, linear, apex round; floating leaves numerous, long-stalked, broadly oval or oblong to elliptic, entire, opaque, thick and rather leathery, 50-100mm long; stipules large, closely veined, 5-8cm long.
Flowers: In spikes or heads; spike dense, 35-50mm long; peduncle twice as 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, 3-8.5mm, with thick pericarp, soft on outside but with bony inner layer.
Habitat: Lakes, ponds, ditches and slow streams.
Distribution: Abundant.
Native status: Native
Of conservation interest: No