The severe winters of 1984/85 and 1985/86 caused a reduction in the numbers of flowering plants from tens of thousands in 1981/82 to 80 in 1986. In spite of the cold spell in january 1987 the subspecies, which is sofar not considered to be indigenous in the Netherlands, has recovered dramatically from the minimum in 1986: roughly 1,000 flowering plants in 1987 and even 8,400 in 1988. Winter 1987/88 was unusually mild and under these circumstances nearly 5% of the 1988 plants developed from 1987 rosettes. The figures 1 and 2 show the seasonal progress of flowering in 1987 as compared with that in 1981 and the daily process of shutting of the flowers in the course of the seasons 1981, 1985 and 1987.