Practical
Plants

Cyathea medullaris

Black Tree Fern

an evergreen member of the Cyathea genus in the family Cyatheaceae.

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Taxonomy and growth

Genus
Cyathea
Foliage
evergreen
Growth rate
slow
Height
9 m
Spread
6 m

Uses

Toxicity

Toxicity warning. The historical record reports a hazard for this plant. Do not use it to decide which parts are safe to eat or use medicinally.

This section contains historical Plants For A Future notes marked noncommercial.

Although we have found no reports of toxicity for this species, a number of ferns contain carcinogens so some caution is advisable[8]. 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[4].

Edible uses

This section contains historical Plants For A Future notes marked noncommercial.

Pith of stem - raw or cooked[11][13][2][5][6]. Rich in starch, the portion below the growing point is the part used[6], do not confuse this with the trunk of the plant, which is made up of a peaty substance from the decaying roots[K]. The pith is used as a coarse sago substitute[7]. The pith contains (dry weight) 3.6% protein, 7.4% starch, 3.1% lipids and 3% simple reducing sugars[5]. 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[5]. Harvesting the stem kills the plant and so cannot normally be condoned[6]. Base of the frond stems - cooked. Young new croziers - cooked[5]. Harvested just before they unfurl, they are juicy and slimy, tasting somewhat like bitter celery[6].

Plant part
Leaves
Plant part
Stem

Environment

Range
Australia, New Zealand.
Habitat
Lowland forests in North, South and Stewart Islands of New Zealand[10].
Shade tolerance
partial shade
Water
high
Hardiness
Zone 9+
Soil textures
sandy, loamy, clay
Soil pH
acid, neutral, alkaline
Tolerates Nutritionally Poor Soil
No
Drought
intolerant

Propagation

This section contains historical Plants For A Future notes marked noncommercial.

Spores - can be surface sown at any time of the year in a light position in a warm greenhouse[3]. 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[3]. Grow on in a shady position in a greenhouse for at least the first two winters and plant out in late spring.

Cultivation

This section contains historical Plants For A Future notes marked noncommercial.

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[1][12][8]. 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[12]. It can bet grown in pots in a shady position in a conservatory or cool greenhouse and placed outside in the summer[1]. It can grow well in very small pots[1]. Members of this genus are rarely if ever troubled by browsing deer[9].

References

  1. F. Chittendon. RHS Dictionary of Plants plus Supplement. 1956 Oxford University Press 1951-00-00

    ↩1↩2↩3

  2. Ewart. A. J. Flora of Victoria.

    ↩

  3. Bird. R. (Editor) Growing from Seed. Volume 4. Thompson and Morgan. 1990-00-00

    ↩1↩2

  4. Schofield. J. J. Discovering Wild Plants - Alaska, W. Canada and the Northwest.

    ↩

  5. Crowe. A. Native Edible Plants of New Zealand. Hodder and Stoughton 1990-00-00 ISBN 0-340-508302

    ↩1↩2↩3↩4

  6. Low. T. Wild Food Plants of Australia. Angus and Robertson. 1989-00-00 ISBN 0-207-14383-8

    ↩1↩2↩3↩4

  7. Hedrick. U. P. Sturtevant's Edible Plants of the World. Dover Publications 1972-00-00 ISBN 0-486-20459-6

    ↩

  8. Huxley. A. The New RHS Dictionary of Gardening. 1992. MacMillan Press 1992-00-00 ISBN 0-333-47494-5

    ↩1↩2

  9. Thomas. G. S. Perennial Garden Plants J. M. Dent & Sons, London. 1990-00-00 ISBN 0 460 86048 8

    ↩

  10. Allan. H. H. Flora of New Zealand. Government Printer, Wellington. 1961-00-00

    ↩

  11. Uphof. J. C. Th. Dictionary of Economic Plants. Weinheim 1959-00-00

    ↩

  12. Arnold-Forster. Shrubs for the Milder Counties.

    ↩1↩2

  13. Usher. G. A Dictionary of Plants Used by Man. Constable 1974-00-00 ISBN 0094579202

    ↩

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