Differences in the time of flowering in populations of European Golden Rod (Solidago virgaurea) on the Åland Islands, SW Finland

Authors

• Ralf Carlsson

Abstract

In northern Åland, SW Finland, I discovered that the yearly development of the Golden Rod (Solidago virgaurea) most probably is dependent on light and partly on the effective temperature sum. The plants, growing on bare cliffs in northern Åland, start flowering about 1,5 months earlier than the plants of the interior of Åland but are much shorter. This may probably be an effect of phenotypic plasticity but may also depend on genetic factors. Plants from the cliffs will, when transplanted to the interior, flower at about the same time as on the cliffs if given enough light. If not, they will flower later and, in any way, they are very small, just like their origins. This speaks in favour of light being a key factor in the development and that the plants of the interior are poor competitors.