Already Charles Darwin, the founder of the theory of evolution, was deeply interested in the cowslip. The cowslip has become a kind of a model organism for scientists, because studies in cowslip allow to draw conclusions about other species as well. Better known model organisms that are studied and performed tests upon include the rat, the fruit fly, and baker’s yeast. That is why the cowslip is a good model organism to study the state of grassland plants and pollinators in your home neighbourhood and in Europe as a whole.

Collectively gathered information about the cowslip helps provide an insight into the state of the cowslip and related species. We can assess which areas are unfragmented biotopes and which areas have taken a turn for the worse.

The cowslip is a heterostylus – it means that the plant can have two types of flowers. These are called the S-type and the L-type. In the S-type flower, the stamen is visible, and in the L-type flower we can see the pistil (photograph). Those are short for short-styled morph and long-styled morph.

                  L-type                                                                                     S-type
L-tüüpi õis
S-tüüpi õis

Different types of flower exchange pollen by way of insects – the pollen from the S-type pollinates the L-type and vice versa. This way, the plant cannot pollinate itself and this prevents genetic erosion – cross-pollination encourages exchange of genetic material and genetic diversity. High genetic diversity is a very important factor in preserving the plants’ vitality and longevity. Read more about genetic diversity here.

Normally in cowslip populations, the occurrence of either types of flower is equal, or more or less 50:50. Imbalance reduces the plants’ opportunities to find a suitable mate, which impedes pollination and the exchange of genetic material. This, in turn, reduces the plants’ vitality. The cowslip’s regular habitats – traditionally managed grasslands – have become increasingly rare in the contemporary landscape. The disappearance of grasslands causes decline in populations that depend on them as a habitat. A massive decline in the cowslip populations can cause imbalances in the occurrence of the L- and S-types of flower to the extent that one of those types completely disappears from the habitat. That is precisely the kind of a possible shift in the balance between the L and S-types caused by changes in the landscape that we want to study – with your help.

The cowslip is a plant pollinated by insects and it depends on the well-being of pollinating insects – honey bees, bumblebees, and butterflies.

How to recognise the cowslip?

The cowslip (Primula veris) is a spring flower. It is a perennial plant, which means that the same plant grows and blossoms in the same place for many years. Its closest relatives in the nature are the bird's-eye primrose, the oxlip, and the common primrose. You can read more about the genus Primula here

How does the cowslip look like?

The cowslip is a herbaceous plant up to 10 to 30 cm tall on average. It has green elongated leaves up to 20 cm long, and one plant can have multiple stems. At the end of the stems, there are deep yellow bell-shaped nodding flowers with orange dots in clusters of 5 to 16 blooms together keeping to one side.
The cowslip is one of the first harbingers of spring. It usually begins to blossom at the beginning of May and flowers usually for a couple of weeks. In a cooler weather, the blossoming can also begin later and last until mid-June.

Where does the cowslip grow?

The cowslip is quite common in Europe, but it is more common in costal areas. That is because it prefers dry or moderately moist limy soils, which are more common in coastal areas. However, this does not mean that the cowslip does not grow in acidic soil at all. It can mostly be found growing on grasslands, in parks, on forest edges and by the roadside. It usually prefers sunnier spots.