Peeking at the undersides of licorice fern fronds at this time of year often rewards you with a display of their orange, naked sori.
The sori are clusters of sporangia, or spore-containing structures (see this illustration of the fern life cycle). The term naked is used because the sori lack a protective covering called the indusium; for comparison, here’s a photograph of sori (partially) covered by indusia on Rumohra adiantiformis.
The epithet glycyrrhiza means sweet root and refers to the genus Glycyrrhiza, a member of the bean family. The root of Glycyrrhiza is better known as licorice (or liquorice). The rhizomes and stems of Polypodium glycyrrhiza are similarly flavoured, hence the common name of licorice fern.
Polypodium glycyrrhiza is distributed along the coastal regions of western North America, as well as the Kamchatka region of Asia. The Hardy Fern Library provides a detailed description of licorice fern.