Common Name:

General Information

Cycas guizhouensis is a slow-growing, evergreen palm-like plant with an unbranched, erect main stem that can eventually be around 60 - 200cm tall; this is topped by a crown of numerous large leaves each around 90 - 200cm long (including petioles). Mature plants often form clumps by suckering at the base[].
The plant is harvested from the wild for local use as a food and a medicine. It is often collected from the wild and grown as an ornamental[].
The population decline of Cycas guizhouensis due to widespread habitat destruction and use as a famine food is estimated to have reduced the population by at least 30% in the last two generations and the decline is expected to continue. The plant is classified as 'Vulnerable' 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 and southeastern China (Guizhou, Guangxi, Yunnan).

Habitat

Typical of low, scrubby forests on steep slopes on limestone bluffs or screes, it is also widespread on steep and almost inaccessable limestone mountains; at elevations from 400 - 1,300 metres[].

Properties

Conservation Status	Vulnerable
Edibility Rating
Medicinal Rating
Habit	Evergreen Shrub
Height	1.50 m
Growth Rate	Slow
Pollinators	Insects
Self-fertile	No
Cultivation Status	Ornamental, Wild

Cultivation Details

Cycas guizhouensis is native to southern China, growing in a region where the average yearly temperature is 18.5°c with summer highs about 38.5°c and winter lows about −2.5°c. Annual rainfall averages 1,000mm, falling mainly in summer. The summers are hot and wet and the winters dry with occasional frosts[].
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.

Eaten as a famine food[].
Cycads have often been used traditionally as a source of food starch, obtained either from the seeds or from the stems, and it is probable that the seed kernels and stem pith of all cycads can be used as food after treatment to remove any toxic principle that may be present (See notes above on toxicity). The starch would appear to be of particular importance as a source of sustenance during hard times or in areas where the food supply is naturally limited[].

Medicinal

The plant is used as a medicine[].

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[].

Add a Comment:

If you have any useful information about this plant, please leave a comment. Comments have to be approved before they are shown here.

Name:

Email(Private):

Message:

Captcha: a square has how many sides?