Calthion palustris – The German Plant Community of the Year

The plant community of the year

Wet meadows on nutrient-rich soils used to be home to species-rich and colorful marsh marigold meadows. However, today, these large areas of wet grassland are being drained or turned into intensive grassland and fields. The Calthion communities support numerous endangered animal and plant species and provide a habitat for countless insects, spiders, and birds. To support their protection and restoration measures, these communities have been selected by the “Floristic-Sociological Working Group” as Plant Community of the Year in 2024. You can recognize them by the following key species:

Marsh marigold (Caltha palustris)

The marsh marigold Caltha palustris belongs to the buttercup family and is widespread in Europe, Asia and North America. Depending on the location, it can grow to a height of 15-60 cm and displays its bright yellow, nectar- and pollen-rich flowers from March. Depending on the location, the flowering period can last until June, and occasionally a second flowering occurs at the end of summer. Typical locations are springs, streams and water-filled ditches, but if you are looking for the Calthion communities, look for wet meadows. There you may also find the other representatives of the community.

Marsh hawk’s-beard (Crepis paludosa)

This yellow-flowered composite plant usually grows to around 30-80 cm tall, but can also reach over a meter in exceptional cases. Finding Crepis paludosa alone does not indicate a Calthion association, as the species is widespread in Germany and only rare in dry areas. Bees, flies and moths pollinate its flowers, which sit on a thin stem above large, serrated leaves. If you find the following species in addition to the two just presented, you have probably found the right location.

Water forget-me-not (Myosotis scorpioides)

From May to September, you can see the 15-80 cm tall, herbaceous Myosotis scorpioides with their hairy leaves in sky-blue bloom. They either stand upright or lean towards the ground, where they can form stolons above ground. The yellow ring (a so-called sap ring) inside the flower is intended to attract pollinators. At the base of the flower, nectar is offered to insects that have a long proboscis, such as many moths, bees and some flies. These flying insects are also often found on:

Bistort (Bistorta officinalis)

Bistorta officinalis can grow between 20 and 100 cm tall. Its pink inflorescences are visible from afar between May and June and attract a large number of pollinators. This species is the preferred food plant for the caterpillars of the blue iridescent fritillary butterfly and the marginal ringed fritillary. It owes its name to its strong rhizome, which is twisted in an S-shape. The genus name Bistorta can also be translated as “twice twisted”. If its habitat becomes dry, it withdraws into this rhizome and survives until it is moist enough to successfully sprout again.

Cabbage thistle (Cirsium oleraceum)

Cabbage thistle meadows are a typical characteristic of Calthion communities. Here, the eponymous  Cirsium oleraceum forms stands. It can reach heights of up to 170 cm and stands out due to its very large but soft and non-prickly leaves. Between June and October, it produces two to six inflorescences per plant, which stand in thistle-like flower heads surrounded by yellow-green, thorny bracts. These are pollinated by bumblebees and their seeds are ultimately spread by birds such as finches, tits and crossbills.

Rushes, sedges and grasses

Of course, marsh marsh meadows are also home to grasses, rudges and sedges. Even if these are not characterized by conspicuous, colourful flowers, they are of great importance for the plant community as a habitat. So to be sure that you have found a *Calthion* community, the following character species should be present: smooth brome Bromus racemosus, common rush Juncus effusus, wood clubrush Scirpus sylvaticus and the sharp-flowering rush Juncus acutiflorus.

Other species

In addition to the characteristic species presented and the typical grasses, other plant species also occur in Calthion communities, which will not be presented individually here. But a click on the link will take you to the respective profile. The broad-leaved marsh orchid Dactylorhiza majalis is quite common in the (few) locations where it occurs. It is one of the orchids that is most tolerant of nutrient input. In addition, the big trefoil Lotus pedunculatus, Cirsium rivulare and water ragwort Senecio aquaticus are among the characteristic species of marsh marigold meadows.

A new badge for you!

If you want to read this message, you have to find 15 of the characteristic species of this plant community. We have just introduced most of them, and we hope that you will now walk through the next wet meadow with your eyes wide open. Of course, the locations of this plant community are rare, so you can also earn the badge if you find the species individually and identify them with Flora Incognita.

Cover picture: Marsh marigold meadow, S. Schneider, tuexenia

 

 

This article was featured as a story in the Flora Incognita app in 2024. In the plant identification app, you will always find exciting information about plants, ecology, species knowledge, as well as tips and tricks for plant identification. Take a look!