Northern Maidenhair,American Maidenhair Fern

Adiantum pedatum

Physical Characteristics

Adiantum pedatum is a FERN growing to 0.5 m (1ft 8in) by 0.5 m (1ft 8in) at a slow rate. See above for USDA hardiness. It is hardy to UK zone 3. The seeds ripen from August to October. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils and prefers well-drained soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It can grow in semi-shade (light woodland). It prefers moist soil.

Distribution

N. America - Alaska to Quebec and Nova Scotia, south to California and Georgia. E. Asia

Habitats

Woodland Garden Dappled Shade; Shady Edge; Ground Cover;

Edible Uses

None known

Medicinal Uses

Antirheumatic Astringent Demulcent Emmenagogue Expectorant Febrifuge Haemostatic Pectoral Tonic The whole plant is considered to be antirheumatic, astringent, demulcent, emmenagogue, expectorant, febrifuge, haemostatic, pectoral and tonic[172, 222, 240]. A tea or syrup is used in the treatment of nasal congestion, asthma, sore throats etc[222]. A decoction of the root was massaged into rheumatic joints[257]. The N. American Indians chewed the fronds and then applied them to wounds to stop bleeding[213]. A strong infusion of the whole plant was has been used as an emetic in the treatment of ague and fevers[257]. This plant was highly valued as a medicinal plant in the 19th century and merits scientific investigation[222].

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].