Thursday, July 13, 2017
Botany picture #248: Gleichenia dicarpa
This is one of my favourite fern photographs: Gleichenia dicarpa (Gleicheniaceae) forming a large thicket at Jervis Bay, Australia, 2011.
While the group does not occur in Germany I have seen quite a few Gleicheniaceae during field work in South America. They are often aggressive colonisers, especially after major disturbances such as landslides, but are said to be very difficult or impossible to cultivate. Also, while I did my PhD there was another PhD student at the same institute who conducted a taxonomic revision of a genus of Gleicheniaceae in the Neotropics, so all things considered these odd-looking ferns were not new to me when I arrived on this continent.
The specific epithet of Gleichenia dicarpa means "two-fruited". Obviously ferns do not have fruits, but this is a reference to the fact that each little pocket on the lower leaf side contains two, and only two, tiny sporangia when the plant is fertile. Given that ferns often produce clusters (sori) of numerous sporangia this low number is rather peculiar in itself.