The royal fern

The royal fern is a tall, attractive plant with a regal name. It grows in large, green clumps that can be more than 1.5 metres tall. It is quite rare in Denmark, but at Bøtø you can find it in several areas where there is some moisture.

How the fern got its name is a bit of a mystery. Which royal person does it refer to? No-one really knows. The royal fern got its scientific name – Osmunda regalis more than 250 years ago.

The first part of the name – Osmunda – maybe refers to King Osmund, who lived in the year 750 in England. But why should he have a fern named after him? Osmunder is also a very old name for the Nordic thunder god Thor – so should it really be named Thor’s fern? Or does the name actually come from the two ancient Latin words ‘os’ and ‘mundus’, which mean ‘clean mouth’ – because the fern was once used to clean the mouth with? Is it just a fern against bad breath?

Regalis means ‘royal’ – and this is perhaps because the fern is large and beautiful and looks like a large, green crown, but it could also be because the central leaves in the fern clumps have golden-brown spore casings (sporangia), so it looks like the plant is wearing a crown.