Scientific name: Potamogeton pusillus L.
Common name: Lesser Pondweed
Description
Habit: Aquatic perennials. Stem only slightly compressed. Rhizome absent; winter-buds axillary, usually slender-fusiform, not strongly ribbed. Hybrids are rather frequent in this genus.
Leaves: Leaves mostly alternate, some opposite, submerged, subtending inflorescences, all with membranous sheath or stipules; very like P. berchtoldii, but with a marginal vein bordering the tip of the leaf; submerged leaves, linear, 0.5-1.4 (1.9)mm wide, acute or obtuse at apex, 3(-5)-veined, the lateral veins inconspicuous; stipules closed, tubular towards the base at least when young, not fibrous-persistent.
Flowers: In spikes or heads; 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, 1.8-2.5mm, with thick pericarp, soft on outside but with bony inner layer.
Habitat: Still or slowly moving water of all kinds.
Distribution: Rather rare.
Native status: Native
Of conservation interest: No