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Common Name: Potato Orchid

General Information

Gastrodia sesamoides is a perennial plant that can grow up to 0.60 metres tall.
It is harvested from the wild for local use as a food.

Known Hazards

None known

Botanical References

,

Range

Australia - Tasmania, Victoria, New South Wales. New Zealand.

Habitat

Open forest and scrub from the coast to the sub-alpine zone, mainly north of latitude 42°s, in the North and South Islands of New Zealand[].

Properties

Edibility Rating
Habit	Perennial
Height	0.60 m
Cultivation Status	Wild

Cultivation Details

We have very little information on this species and do not know if it will be hardy in Britain. A saprophytic herb, it is without green parts and is entirely dependant upon a fungus for its nutriment[, ]. This makes it very difficult to cultivate outside its native range. As well as its fungal host, it also requires a damp humus-rich soil in a sheltered woodland position[].
Orchids are, in general, shallow-rooting plants of well-drained low-fertility soils. Their symbiotic relationship with a fungus in the soil allows them to obtain sufficient nutrients and be able to compete successfully with other plants. They are very sensitive to the addition of fertilizers or fungicides since these can harm the symbiotic fungus and thus kill the orchid[].

Edible Uses

Root - raw or cooked. It resembles a beetroot in flavour but is watery and insipid[, , , ]. The root can be up to 15cm long and 4cm thick[].
Leaves. Eaten by the Australian Aborigines in Tasmania[].

Medicinal

None known

Other Uses

None known

Propagation

Seed - surface sow, preferably as soon as it is ripe, in the greenhouse and do not allow the compost to dry out. The seed of this species is extremely simple, it has a minute embryo surrounded by a single layer of protective cells. It contains very little food reserves and depends upon a symbiotic relationship with a species of soil-dwelling fungus. The fungal hyphae invade the seed and enter the cells of the embryo. The orchid soon begins to digest the fungal tissue and this acts as a food supply for the plant until it is able to obtain nutrients from decaying material in the soil[]. It is best to use some of the soil that is growing around established plants in order to introduce the fungus, or to sow the seed around a plant of the same species and allow the seedlings to grow on until they are large enough to move.
Division in autumn. The plant is very intolerant of root disturbance, any moving or dividing should be attempted in the autumn, keep a large ball of soil around the plant[].