Cycas szechuanensis is closely allied to Cycas taiwaniana. It was rediscovered in the wild only in 1999, in eastern Fujian Province. Before this, it had been presumed extinct, or at one time regarded as conspecific with Cycas guizhouensis (Chen & Stevenson 1999)[].

Common Name:

General Information

Cycas szechuanensis is a slow-growing, evergreen, palm-like plant with a short, erect main stem that can eventually be up to 2 metres tall and 15 - 25cm in diameter; this is topped by a crown of 6 - 20 large leaves each around 120 - 380cm long[].
The plant is commonly cultivated for its edible seeds and medicinal uses in parts of China338]. It is often grown as an ornamental[].
Population decline of Cycas szechuanensis over three generations is estimated as more than 80% due to habitat degradation and over-exploitation for the ornamental trade. The plant is classified as 'Critically Endangered' in the IUCN Red List of Threatened Species(2010)[].

Known Hazards

We have no specific information for this species, but most if not all members of this genus are believed to contain toxins. The two main toxic compounds that have been identified are cycasin and macrozamin. When ingested in sufficient quantities, these compounds are extremely poisonous to humans and many other animals, and have been shown to cause liver damage and cancer. Cycasin and macrozamin have a cumulative effect upon the body and are suspected of causing neurological disorders when ingested in small amounts over long periods of time.
There is a long history of human use of this genus as a starch-rich food, but it should be noted that the plants needed to be treated in various ways in order to remove any toxic principles. Caution should be exercised even with properly prepared foods, since even then regular consumption may lead to severe health problems and death. Since many of these species are becoming increasingly rare in the wild, this is probably a food best left to times of food shortage when other, better foods, are not available[, ].

Botanical References

Range

E. Asia - southern China (Fujian, Guangdong)

Habitat

Moist closed forests and woodlands[].

Properties

Conservation Status	Critically Endangered
Edibility Rating
Medicinal Rating
Habit	Evergreen Tree
Height	1.50 m
Growth Rate	Slow
Pollinators	Insects
Self-fertile	No
Cultivation Status	Cultivated, Ornamental, Wild

Cultivation Details

Cycad species are most commonly found in sub-tropical to semi-arid topical climates that are generally frost-free or only experience occasional light frosts. Although they mainly prefer a summer rainfall climate with cool, dry winters, most of them will adapt easily to a Mediterranean climate with its dry summers and moist winters Rainfall must be at least 350mm annually for cycads to survive. Some exceptional tropical habitats may have rainfall in excess of 5,500mm annually[].
An almost universal requirement for cycads is a well-drained but moisture-retentive soil, and by far the best soils are sandy gravels and light loams which provide the required drainage and aeration necessary for good growth. Cycads will generally not grow well in clay soils unless those soils are heavily amended with sand and organic matter[]. A neutral soil (pH 7), is generally best for most species of cycads and allows the proper absorption of nutrients. A slightly acid soil is better for most cycads than a basic one[].
Species in this genus can usually be transplanted easily even when quite large. The best time for moving them is just before the beginning of a new growing season, the roots being trimmed if they are damaged and perhaps some leaves being removed. New roots should develop quickly as the season progresses[].
Species in this genus form structures known as coralloid roots. These roots branch off from the taproot or secondary roots and are distinctive in that they grow laterally or upward, forming a nodular mass at the apex. These coralloid roots occur slightly below or slightly above the soil surface and generally contain cyanobacteria, also known as blue-green algae. These are able to fix atmospheric nitrogen and make it available as a nutrient to the plant. The ability to extract this important nutrient from the air explains how many cycad species are able to survive on almost sterile soils[].
A dioecious species, with individual plants producing either all male or all female cones. Therefore both male and female forms of the plant need to be grown if seed is required[]. On very rare occasions, usually when a plant has been under severe stress, it can change sex and produce either all female or all male cones[].

Edible Uses

Species in this genus are generally toxic unless the food is prepared correctly. See notes above on toxicity.

Starch is extracted from the trunk for food and distiller's purpose[].

The seeds are edible after cooking[].

Medicinal

The seeds are used medicinally for suppressing asthma and coughs[].

Other Uses

None known

Propagation

Seeds - best sown as soon as they are ripe, though the seeds of many species will take a few months to finish maturing the embryo before they are ready to germinate. Sow the seeds in a tray in a freely-draining medium and place in moderate shade. Bottom heat at about 27°c will hasten seed germination dramatically. Young roots are quite brittle and once germination takes place, the root grows rapidly. It is important to pot up the seedlings at this time in order to give them enough root-space. Grow on the plants in pots until large enough to plant out[].
Division of off-sets or suckers is best carried out just before the plant comes in to new growth at the start of the growing season[].

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