Both the scientific name refers Geranium and the German name geranium to the form of long-stemmed fruit, where you can see the head and the elongated neck of a stork or a crane. The fruit is made up of very long carpels which bear only on the bottom two seeds. Of these, only one developed, while the upper sterile part as a "beak" grows. Botanically it is a gap fruit, as these splits at maturity in their five fruit trays. The seeds are spread in all species by the explosive dehiscence of the drying beak. When forest Cranesbill roll for example, the five fruit trays suddenly one of the central column and from each and up. The seed is thereby catapults hurled far up to 3 meters.
Geraniums include this mechanism to spread the so-called Austrocknungsstreuern (botanically known as ballochore Autochorie).
When Rupert herb can also observe the Herpochorie. While the Herpochorie at the Pasque and the closely related species of heron beak a strategy to Nahausbreitung, it is used here serves to give the seeds optimal launch conditions: after the seeds of the Ruprecht weed through the mechanism described above has been an explosion hurled far up to six feet, the seed drill by hygroscopic movements in the earth. This is due to the fact that expand the seeds in damp weather and shrink in dry weather again.