Common name: Licorice Fern

Scientific Name: Polypodium glycyrrhiza

"Polypodi"= many-footed fern; Greek

"glyc"= sweet; "rhiza"= root; Greek

Description: The long, pointed-trangle fronds of this evergreen fern range in size from 10-70cm on average. Its leathery leaves are once pinnately divided, with a light brown stipe; they are usually shorter than 50cm (20 inches) long. Its rhizome (root-like structure) has a scaly, reddish-brown outer covering, with a sweet, succulent inside that resembles the taste of licorice. Its sori (seed-like sack) of 3mm across or larger, are oval to round and located in a single file row on either side of a main vein on the underside part of the leaf. The sori (sack of spores) lack an indusium (a membrane that covers the sori) (Pojar and MacKinnon 1994).

Geographical range: This fern is found throughout coastal regions of the Pacific Northwest, extending from Northern California to Northern Alaska.

Habitat: Polypodium glycyrrhiza is found on wet, mossy ground, logs, rocks, and most commonly as an epiphyte on trees. It is predominantly found on Big leaf maple trees in the lowland, coastal forests of the Pacific Northwest (Pojar and Makinnon 1994).

Reproduction: Ferns reproduce both by seed-like structures called spores and vegetatively. Most ferns have spores on the underside of their leaves. These spores are stored in sacks called sori. When the climate and moisture are right, the fern releases its spores; some are blown through the wind, some travel on animals, and others fall to the ground. Each spore contains only one set of chromosomes (haploid) that are found in the fern cells. Thus, a spore itself cannot grow into a plant, but must undergo a process of growth called "alternate generation". A spore will grow into a gametophyte plant. A gametophyte is a premature fern that produces separate male and female parts of the plant. The gametophyte tends to be a small (1cm), heartshaped plant with fine hair-like roots called rhizoids. In this stage, the gametophyte produces tiny reproductive structures; the spherical antheridia which holds the sperm and the archegonia, which holds a single egg. The sperm swims in the water on the prothallus and finds a archegonia, which it fertilizes. The fertilized egg forms a zygote from which a new plant grows. The plant incubates inside the prothallus for a short period of time until it is developed enough to sink its roots into the soil and grow (Keater and Heady 1981).

Input requirements (food supply): Like all plants, the Licorice fern depends on photosynthesis for its survival. It takes nutrients (from the soil that has accumulated in the moss mats in which the fern resides), air, and water, and using the energy of the sun, converts these elements into useful sugars.

Role in the ecosystem: The licorice fern stabilizes forest canopy soil and substrate with its extensive network of rhizomes, supporting a place for other epiphytes (moss and lichen) to grow. It also provides food for herbivorous insects.

Use as a Human Resource: Licorice fern rhizoids were historically chewed as a snack by the Squamish, Sechelt, Comox, Haida, Nuxalk, and Kwakwaka’wakw tribes. Occasionally the rhizomes were eaten raw or cooked by coastal Native American tribes. The rhizomes are also important as medicine for sore throats and coughs, and as a sweetener for cooking (Pojar and Makinnon 1994).

Notes: This fern is often mistaken for its cousin, Polyposium scouleri (leather fern), which is located strictly on the coast in high saline, foggy, environments. However, Polyposium scouleri has incredibly leathery leaves and does not taste like licorice (Pojar and Mackinnon 1994).