Nymphaea L.

Abstract

Accounts of Nymphaea and N. alba for the "Bio-logical Flora of the British Isles". Detailed studies on meristic variation in N. alba in Britain shows that the sp. is probably not less variable here than in Sweden or in Germany. Isolated colonies composed of plants possessing unusual combinations of characters occur throughout its range and may have arisen through either genetical drift or reproduction of a single original colonist with unusual genetical attributes. The history of "N. occidentalis (Ostenf.) Moss" is given and it is concluded that, as with several other variants, there is no justification for giving it taxonomic recognition as a sp. The closely allied sp. N. Candida, however, differs from N. alba in various qualitative, as well as quantitative features; it is almost vicarious in some areas (e.g. Scandinavia), and hybrids between these 2 spp. appear to have reduced fertility. Habitat studies show that N. alba does not withstand as much water movement as Nuphar lutea, although it can tolerate slightly higher degrees of salinity and acidity. Details of its germination, morphology, floral biology, reproduction, cytology and distribution are given as well as lists of spp. with which it is associated in the Britannic area.