Nuphar japonica

Nuphar japonica, known as East Asian yellow water-lily, is a perennial, aquatic, rhizomatous, herb in the family Nymphaeaceae native to Japan, Korea, and Russia.
Nuphar japonica is one of three species in the genus Nuphar that is dispersed in the same geographical location of the Saijo Basin, an area in the Hiroshima Prefecture of Japan.

Description

Vegetative characteristics

Nuphar japonica is a perennial, aquatic, rhizomatous, herb with 1–3 cm thick rhizomes. The leaves are submerged, floating, or emerged. The leaf blade is 12–35 cm long, and 6–18 cm wide. The terete petiole is 3–10 mm wide.

Generative characteristics

The yellow to red, solitary, 4–5 cm wide flowers have a long, cylindrical peduncle. The flowers have five sepals and 10–18 petals. The gynoecium consists of 15–16 carpels. The 2–3.5 cm long, and 1.6–2.3 cm wide, urceolate, green, long-necked fruit bears ovoid seeds.

Cytology

The chromosome count is 2n = 34.

Taxonomy

It was published by Augustin [Pyramus de Candolle] in 1821. It is placed in the section Nuphar sect. Nuphar.

Natural hybrids

Padgett is a natural hybrid between Nuphar japonica and Nuphar pumila.

Etymology

The specific epithet japonica means of Japan.

Phytochemistry

N. japonica contains the alkaloids nupharidin, 1-desoxynupharidin, nupharamine, methyl and ethyl esters of nupharamine. The fruits also contains the alkaloids nupharine, beta-nupharidin, desoxynupharidin. In the rhizomes are found the steroid sitosterol, alkaloids acids, higher fatty acids and the ellagitanins nupharin A, B, C, D, E and F.