CC BY 4.0
Watermoss
Salvinia formosa, Mittelmiozän
About the object
These two leaf fossils in the marlstone slab from the Bohlinger Schlucht have been excellenty preserved. A free-floating aquatic plant leaf belonging to a species of floating fern Salvinia formosa can be seen alongside one half of a preserved willow leaf Salix lavateri.
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Floating ferns comprise a genus of aquatic plants, which today are predominantly found in the standing and slowly-flowing waters of the tropics. They are not rooted in the soil, instead they float on the surface of the water. Salvinia formosa was native to Europe 13.5 million years ago. A single plant consists of two floating leaves and one submerged leaf. Inside the floating leaves were pouches of air, which here appear as small pustules on the fossil specimen. The plants achieve their buoyancy thanks to these air pouches as well as their water-repellent leaf structure and a coating of wax. The submerged leaf resembles a thin root, which extended under water and was responsible for the uptake of nutrients. These leaves effectively assumed the function of roots.