Licorice Fern

Polypodium glycyrrhiza

Physical Characteristics

Polypodium glycyrrhiza is a FERN growing to 0.5 m (1ft 8in) by 0.5 m (1ft 8in) at a medium rate. See above for USDA hardiness. It is hardy to UK zone 7. The seeds ripen from November to March. The plant is not self-fertile. It is noted for attracting wildlife. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It prefers moist soil and can tolerate drought.

Distribution

Western N. America - Alaska to California.

Habitats

Woodland Garden Dappled Shade; Shady Edge; North Wall. In. East Wall. In.

Edible Uses

Edible Parts: Root Edible Uses: Root - raw or cooked[257] The root is sweetly liquorice-flavoured but is thin and fibrous and virtually inedible[200]. The root was commonly chewed for its very pleasant flavour by many native North American Indian tribes[256, 257]. It was often used as an appetiser, especially for children who would not eat[256]. Apart from its used as a pleasantly flavoured chew, it was seen as a famine food and was only used when there was a shortage of better foods[177, 257].

Medicinal Uses

Alterative Carminative Haemostatic Pectoral Liquorice fern was employed medicinally by several native North American Indian tribes who used it especially as a treatment for a variety of chest complaints[257]. It is little, if at all, used in modern herbalism. The rhizomes are alterative, carminative, haemostatic and pectoral[257]. The raw rhizomes have been eaten, or an infusion has been used, in the treatment of coughs and colds, chest pains, shortness of breath and VD[257]. The roots have been chewed, and the juice swallowed, as a treatment for sore throats and the spitting or vomiting of blood[257]. A tea of the pounded boiled rhizomes, mixed with fir needles, has been used to treat measles[213]. Coughs have been treated by chewing and slowly swallowing the juice of the roasted rhizome[213]. The roots have been used in the treatment of colds and sore throats[256].

Known Hazards

Although we have found no reports of toxicity for this species, a number of ferns contain carcinogens so some caution is advisable[200]. Many ferns also contain thiaminase, an enzyme that robs the body of its vitamin B complex. In small quantities this enzyme will do no harm to people eating an adequate diet that is rich in vitamin B, though large quantities can cause severe health problems. The enzyme is destroyed by heat or thorough drying, so cooking the plant will remove the thiaminase[172].