Scientific name: Potamogeton gramineus L.
Common name: Various-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 membranous, oblong to narrowly lanceolate or oblanceolate, up to 14 x 1.2cm, acute, tapered at the base but not stalked; floating leaves, if present, opaque, elliptic, up to 9.5 x 3.4cm; stipules conspicuous, herbaceous.
Flowers: In spikes or heads; spike dense, 25-35mm long; peduncle much longer; 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, 2.5-3mm long, dark green, with thick pericarp, soft on outside but with bony inner layer.
Habitat: Rivers and lakes.
Distribution: Mainly in the Northern half. Occasional.
Native status: Native
Of conservation interest: No