Nymphaea × borealis

Nymphaea × borealis is a species of waterlily native to Sweden, Poland, Germany, the Czech Republic, and East European Russia. It is a natural hybrid of Nymphaea alba and Nymphaea candida.

Generative characteristics
The filament is lanceolate. The yellow stigma has a hemispherical, short projection in the centre of the stigma.

Cytology
It exhibits an intermediate genome size.

Generative reproduction
Nymphaea × borealis exhibits lower fertility and pollen production.

Natural hybridisation
Nymphaea × borealis can be formed in areas of sympatric occurrence of the parent species, but the natural hybridisation of both parent species is not very frequent. Genetically confirmed hybrids are a rare occurrence.

Publication
It was first described by Edmond Gustave Camus in 1898.