N. pumila grows in oligotrophic or mesotrophic water in lakes, sheltered bays, ditches and pools in marshes and bogs. It persists in one eutrophic lake in Shropshire. Lowland; upland records require confirmation.
This species has long been confused with the hybrid N. lutea x N. pumila (N. x spenneriana), and the distribution of both is still poorly known. However, it is much better recorded than in the 1962 Atlas.
Circumpolar Boreal element; absent from western N. America and the eastern population is sometimes distinguished as N. microphylla.
There are no images in this gallery.
Light (Ellenberg): 7
Moisture (Ellenberg): 11
Reaction (Ellenberg): 6
Nitrogen (Ellenberg): 4
Salt Tolerance (Ellenberg): 0
January Mean Temperature (Celsius): 1.7
July Mean Temperature (Celsius): 12.5
Annual Precipitation (mm): 1680
Perennation - primary
Life Form - primary
Clonality - primary
Count of 10km squares in Great Britain: 68
Count of 10km squares in Ireland: 0
Count of 10km squares in the Channel Isles: 0
Atlas Change Index: 0.87
Scarce Atlas Account
Nuphar pumila (Timm) DC.
This water-lily grows in water 0.6-2.4 metres deep in sheltered lakes, in the oxbows and sheltered bays of rivers, in ditches and in pools in marshes and bogs. In Scotland it is found in oligotrophic, or, more frequently, mesotrophic sites, some of which receive base-rich drainage water. At the isolated sites in Shropshire it grows with N. lutea and Persicaria amphibia in sheltered bays in base-rich, eutrophic meres over glacial drift. These meres might, however, have been less eutrophic in former times. It is found over a range of substrates including mud, silt and peat. It ranges from near sea-level to 300 metres; a record from 520 metres near Lochan nan Damh (White 1898) is probably correct but requires confirmation.
N. pumila is a rhizomatous perennial. The flowers are not automatically self pollinated but are visited by insects which may effect either self- or crosspollination. The seeds lack morphological adaptations for animal dispersal, and are killed by desiccation and completely digested when eaten by birds or fish. The main chance of dispersal must be by water movement. Most populations are fertile, but at Avielochan a population shows reduced fertility, probably because the plants have undergone introgression with N. lutea (Heslop-Harrison 1953).
N. pumila was confused for many years by British botanists with the widespread hybrid N. lutea x pumila (N. x spenneriana). The taxonomy was clarified by Heslop-Harrison (1953) but the distribution cannot be revised adequately on the basis of herbarium material and a field survey is needed to establish the distribution of this species and the hybrid. There is no evidence that the species has declined in Scotland, but the plant has been lost from two of its three outlying sites in Shropshire, probably because of eutrophication.
N. pumila is a circumboreal species. It is frequent in northern Europe but is known from the Alps and other very scattered localities south to 43 °N in Spain. For maps of its European and world distributions, see Jalas & Suominen (1989) and Hulten & Fries (1986).
For an account of the ecology of this species, see Heslop-Harrison (1955).
C. D. Preston
Atlas text references
1986. Atlas of north European vascular plants north of the Tropic of Cancer. 3 vols.
Jalas & Suominen (1989)
1965. Vergleichende Chorologie der zentraleuropäischen Flora. Volume 1. 2 vols.
1997. Aquatic plants in Britain and Ireland.
1994. Scarce plants in Britain.