Abstract
Henbane Hyoscyamus niger is a truly exceptional plant. Few species in our flora are as enveloped with mysticism and magic as henbane. The species is monocarpic with both annual and biennial forms. Biennial plants grow a leaf rosette during the first season. This article sums up a decade of observations of henbane on Hovedøya, a calcareous island just outside Oslo, Norway. The authors present an account of the regularity of leaf rosettes emerging on years following digging work when soil masses are turned around and the seed bank is activated. About half of the individuals become fertile the second year, and the third year the plant is gone without a trace, but the seed bank is recruited. After each disturbance henbane is germinating only the first year; there is no establishment in the following years. Considering that these digging works have been carried out in different places on the island, the total seed bank of henbane on Hovedøya must be considerable.
http://nhm2.uio.no/botanisk/nbf/blyttia/