- Name also: Pygmy Water-lily, Pygmy Waterlily, Small White Water-lily
- Family: Water-lily Family – Nymphaeaceae
- Growing form: Perennial herb. Strong-rooted aquatic plant with floating leaves.
- Height: 0.5–2 m (1.5–7 ft.)
- Flower: Bowl-shaped, 2.5 cm (1 in.) wide, with a quadrangular receptacle. The numerous petals are white, rarely red or purple. Sepals four. Anthers pale yellow. Pistils of several fused carpels.
- Leaves: Floating leaves with a 7–12 cm (2.8–5 in.) long, oval to oblong, uneven blade. Leaf-stalk thin and flattened. Submerged leaves with smooth blade.
- Fruit: Berry.
- Habitat: On soft bottom in sheltered forest ponds and lakes, and slow moving waters.
- Flowering time: June–August.
Red-flowered variety of Finnish water-lily is protected.
Water-lilies (Nymphaea spp. and Nuphar spp.) are among the most primitive dicotyledons. Features such as spiral arrangement and great numbers of floral leaves are considered to be signs of this. On the other hand, the floating leaves represent a high level of specialisation. Large-flowered white water-lilies are perennials with strong rootstocks, and broad- and entire-bladed submerged and floating leaves.
Worldwide approx. 50 water-lily species are known. In Finland 2 (the other one having 2 subspecies). Finnish water-lily has the smallest flowers of the white water-lily species growing in Finland, but many think they are the most beautiful ones. The species is absent from the other Nordic countries and Central Europe.