Black Spleenwort

Asplenium adiantum-nigrum

Physical Characteristics

Asplenium adiantum-nigrum is an evergreen Fern growing to 0.5 m (1ft 8in). See above for USDA hardiness. It is hardy to UK zone 6. It is in leaf all year, and the seeds ripen from June to October. Suitable for: light (sandy) and medium (loamy) soils and prefers well-drained soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It can grow in full shade (deep woodland) or semi-shade (light woodland). It prefers moist soil.

Distribution

Most of Europe south of the Faroes, including Britain, to the Himalayas, N. and S. Africa.

Habitats

Woodland Garden Dappled Shade; Shady Edge; not Deep Shade; Hedgerow; North Wall. In.

Edible Uses

None known

Medicinal Uses

Bitter Contraceptive Diuretic Emmenagogue Expectorant Laxative Ophthalmic Pectoral The plant is bitter, diuretic, laxative and ophthalmic. It is taken internally to treat diseases of the spleen, jaundice and ophthalmia. It is said to produce sterility in women. A decoction or syrup made from the fronds is emmenagogue, expectorant and pectoral. It is used to relieve troublesome coughs.

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].