A biennial herb of dry, calcareous soils, particularly those overlying chalk, and on coastal sandhills, sandy open areas and waste ground. It prefers disturbed ground, including rabbit warrens and building sites. Lowland.
There is a continuous archaeological record of H. niger in Britain from the Bronze age onwards. Declines before 1930, particularly in Ireland, were evident in the 1962 Atlas and have continued markedly since then, mostly through the increased use of herbicides.
As an archaeophyte H. niger has a Eurosiberian Southern-temperate distribution, but it is widely naturalised so that it is now Circumpolar Southern-temperate.
Light (Ellenberg): 8
Moisture (Ellenberg): 4
Reaction (Ellenberg): 7
Nitrogen (Ellenberg): 9
Salt Tolerance (Ellenberg): 0
January Mean Temperature (Celsius): 4
July Mean Temperature (Celsius): 15.7
Annual Precipitation (mm): 799
Height (cm): 80
Perennation - primary
Life Form - primary
Clonality - primary
Count of 10km squares in Great Britain: 796
Count of 10km squares in Ireland: 87
Count of 10km squares in the Channel Isles: 5
Atlas Change Index: -1.38
Scarce Atlas Account
Hyoscyamus niger L.
Status: not scarce
This lowland, biennial herb tends to occur on disturbed ground and in sandy coastal areas. H. niger is usually to be found on calcareous soils where there is little competition from coarse vegetation. In some seaside sites it grows alone and thrives in very sandy soil where other plants which lack its deep tap-root are unable to maintain a foothold. It is frequently to be round inland on chalk downs, particularly around rabbit-warrens where other more palatable competing species have been grazed away and the soil is continually disturbed.
Reproduction is by moans of its plentiful seeds. These germinate erratically and there is strong evidence that buried seeds remain viable fur many years, awaiting disturbances that will bring them to the surface. Distribution of seeds to new sites is probably by wind, although many occurrences in new sites are clearly a result of human activities, since H. niger turns up regularly on refuse-tips where builders’ rubble has been dumped.
H. niger is declining due to loss of suitable habitat to coastal development. to more intensive use of farmland and general 'tidying up' of waste places. Several factors ailed its prospects liar future survival. Livestock fanners uproot and destroy H. niger on sight, since it is extremely poisonous to animals (and humans). However, it has been cultivated for many centuries for medical purposes, as a source of several important alkaloids, which may have assisted its spread. Recent records suggest that it may be introduced as a seed impurity in leguminous forage crops.
The native range of H. niger has been obscured by its spread as a medicinal plant. It probably originates in the Mediterranean region and western Asia, but is now widespread in the northern hemisphere and also recorded in Australasia.
In Britain, as in Europe, it is virtually impossible to separate localities where the species is native (or at least long-established) from those where it is a recent introduction. All records are therefore mapped together irrespective of status.
V. A. Johnstone