Herb: Black Tree Fern

Latin name: Cyathea medullaris

Synonyms: Cyathea medularis

Family: Cyatheaceae (Tree Fern Family)

Edible parts of Black Tree Fern:

Pith of stem - raw or cooked. Rich in starch, the portion below the growing point is the part used, do not confuse this with the trunk of the plant, which is made up of a peaty substance from the decaying roots. The pith is used as a coarse sago substitute. The pith contains (dry weight) 3.6% protein, 7.4% starch, 3.1% lipids and 3% simple reducing sugars. The stem is often damaged some time prior to harvest in order to improve the flavour of the pith, a slimy red bitter gum exudes from the wound. Harvesting the stem kills the plant and so cannot normally be condoned. Base of the frond stems - cooked. Young new croziers - cooked. Harvested just before they unfurl, they are juicy and slimy, tasting somewhat like bitter celery.

Description of the plant:


9 m
(30 feet)

Habitat of the herb:

Lowland forests in North, South and Stewart Islands of New Zealand.

Propagation of Black Tree Fern:

Spores - can be surface sown at any time of the year in a light position in a warm greenhouse. Keep moist by standing the pot in shallow water or by enclosing it in a plastic bag. Germinates in 1 - 3 months at 25C. Prick out patches of the young plants into small pots and stand the pots in shallow water until the plants are well established. Grow on in a shady position in a greenhouse for at least the first two winters and plant out in late spring.

Cultivation of the herb:

Lowland forests in North, South and Stewart Islands of New Zealand.

Medicinal use of Black Tree Fern:

None known

Known hazards of Cyathea medullaris:

Although we have found no reports of toxicity for this species, a number of ferns contain carcinogens so some caution is advisable. 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.

Plant information taken from the Plants For A Future.