[3] Royal fern is a large perennial herb with stout ascending rhizomes that over many years build up a woody, trunk-like base covered by interwoven roots, 1 m or more high.

Many of the fronds have a terminal fertile portion, where the blade is reduced almost to the midrib and densely covered with brown sporangia.

[4][5] The native range of royal fern is throughout Europe, North Africa and the Middle East as far as Iran, from Norway south to Algeria.

It is listed as introduced in New Zealand, but its presence throughout North America[6] is based on the taxonomic uncertainty about whether Osmunda spectabilis should be considered a separate species or not.

According to Slavic mythology, the sporangia, called "Perun's flowers", have assorted magical powers, such as giving their holders the ability to defeat demons, fulfill wishes, unlock secrets, and understand the language of trees.

In earlier traditions, they must be collected on Kupala Night; later, after the arrival of Christianity, the date is changed to Easter eve.

Either way, the person wanting to collect Perun's flowers must stand within a circle drawn around the plant and withstand the taunting or threats of demons.