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Common Name: Japanese Sago Palm

General Information

Cycas revoluta is an evergreen tree that can grow up to 3.50 metres tall.
It is harvested from the wild for local use as a food and medicine

Known Hazards

The plants contain alkaloids of carcinogens and also an amino-acid that causes chronic nervous disorders[]. Regular consumption of the plant leads to severe health problems and death. This toxic principle can be removed if the food is properly prepared but consumption of the plant still cannot be recommended because its use often means the death of the plant and it is becoming rare in the wild.

Botanical References

, ,

Range

E. Asia - China, Japan.

Habitat

Found mainly on the sea shore in S. Japan[]. Thickets on hillsides on islands, sparse forests on mainland at elevations of 100 - 500 metres in Fujian, China[].

Properties

Edibility Rating
Medicinal Rating
Habit	Evergreen Tree
Height	3.50 m
Growth Rate	Slow
Pollinators	Insects, wind
Self-fertile	No
Cultivation Status	Wild

Cultivation Details

Requires a strong loam with sharp sand and good drainage[]. Succeeds in dry soils. Requires a sunny position[].
Although it is the hardiest cycad, this species is not fully hardy in Britain but can tolerate occasional lows to about -5°c so long as the crown is protected[, ] and so is worthwhile trying outdoors in a sheltered position in the mildest areas of the country[]. Alternatively, it can be given greenhouse or conservatory protection over the winter and be placed outdoors in the summer[]. Plants are very slow growing[, ].
This plant is often used as a food source in its native range but recent research has shown that it can cause chronic nervous disorders if it is not treated properly[]. Overall its use is not to be recommended, especially since it is becoming rare in the wild.
The plants produce special upward growing roots where nitrogen is produced in symbiosis with algae[].
Dioecious, male and female plants must be grown if seed is required.

Edible Uses

Seed - raw or cooked[, , ]. They can be dried and ground into a powder then mixed with brown rice and fermented into 'date miso' or 'sotetsu miso'[]. Caution is advised, see the notes above on toxicity.
The heart or pith of the trunk is sliced and eaten baked or powdered. A toxic principal must first be removed[]. A starch can be extracted from this pith and is used for making dumplings[]. It is very sustaining[, ].

Medicinal

The leaves are used in the treatment of cancer and hepatoma[].
The terminal shoot is astringent and diuretic[].
The seed is emmenagogue, expectorant and tonic[]. It is used in the treatment of rheumatism[]. Substances extracted from the seeds are used to inhibit the growth of malignant tumours[].

Other Uses

None known

Propagation

Seed - best sown in a greenhouse as soon as it is ripe, 2cm deep in individual pots which are then sealed in plastic bags to keep them moist until germination takes place. Germinates in 1 - 3 months at 25°c[]. Pre-soak stored seed for 24 hours in warm water then treat as above.
Division of suckers in the spring.