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Common Name: Black Tree Fern

General Information

Cyathea medullaris is a Evergreen Fern up to 9.00 metres tall.
It is harvested from the wild for local use as a food.

Known Hazards

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[].

Botanical References

,

Range

Australia, New Zealand.

Habitat

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

Properties

Edibility Rating
Habit	Evergreen Fern
Height	9.00 m
Growth Rate	Slow
Cultivation Status	Wild

Cultivation Details

Prefers a humus-rich soil in a sheltered light position but with shade from strong sun It grows well in light woodland. Requires shelter from winds, an abundance of moisture at its roots and its trunk kept wet[, , ].
A very ornamental plant, it succeeds outdoors in woodland conditions in the mildest parts of the country, but is tender in most parts of Britain[]. It can bet grown in pots in a shady position in a conservatory or cool greenhouse and placed outside in the summer[]. It can grow well in very small pots[].
Members of this genus are rarely if ever troubled by browsing deer[].

Edible Uses

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[].

Medicinal

None known

Other Uses

None known

Propagation

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 25°c. 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.