The Control of Flowering in the Monocarpic Perennial Carlina vulgaris

In natural populations of the biennial Carlina vulgaris more than 95% of the individuals delayed flowering past the second year. The probability of flowering increased with (in order of importance) increasing size before boltining in June, size before the winter (November of the year before flowering) and growth in spring (April to June). No significant effect of age was found. In a nutrient rich experimental garden 58% of the individuals flowered in their first year. Laboratory experiments showed that all individuals flowered without cold if they were given optimal growing conditions (...)