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Useful Tropical Plants

Cycas siamensis

Miq.

Cycadaceae

+ Synonyms

Cycas baguanheensis L.K.Fu & S.Z.Cheng

Cycas boddamii Van Geert

Cycas immersa Craib

Cycas intermedia B.S.Williams

Epicycas siamensis (Miq.) de Laub.

Common Name:

Cycas siamensis
Drawing of the plant
Photograph by: L’ Illustration horticole, vol. 28: t. 433 (1871)
Creative Commons License

General Information

Cycas siamensis is a slow-growing, deciduous, palm-like plant with an erect main stem that can eventually be around 100 - 150cm tall, though usually shorter; this is topped by a crown of erect to spreading leaves each around 80 - 100cm long[
1935
Title
The Cycads
Publication
 
Author
Whitelock L.M.
Publisher
Timber Press; Portland, Oregon
Year
2002
ISBN
0-88192-522-5
Description
An excellent book dealing with the eleven different genera and almost 300 species of plants we know as Cycads. There are detailed descriptions and a host of other information for each species.
].
The plant is harvested from the wild for local use as a food and medicine. It is sometimes grown as an ornamental.
This species is widespread and locally extremely abundant. However, the population is estimated to have declined by more than 30% over the past 90 years based on extent of conversion to agriculture and due to collecting for the ornamental trade. The plant is classified as 'Vulnerable' in the IUCN Red List of Threatened Species(2013)[
338
Title
IUCN Red List of Threatened Species
Publication
 
Author
 
Website
http://www.iucnredlist.org/
Publisher
 
Year
0
ISBN
 
Description
A list of plants under threat and facing possible extinction, usually with brief details of the threats and information on habitat.
].

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[
1935
Title
The Cycads
Publication
 
Author
Whitelock L.M.
Publisher
Timber Press; Portland, Oregon
Year
2002
ISBN
0-88192-522-5
Description
An excellent book dealing with the eleven different genera and almost 300 species of plants we know as Cycads. There are detailed descriptions and a host of other information for each species.
,
K
Title
Plants for a Future
Author
Ken Fern
Description
Notes from observations, tasting etc at Plants For A Future and on field trips.
].

Botanical References

990
Title
The Cycad Pages
Publication
 
Author
 
Website
http://plantnet.rbgsyd.nsw.gov.au/PlantNet/cycad/wlist.html
Publisher
Royal Botanic Gardens, Sydney.
Year
2012
ISBN
 
Description
A website dedicated to the various species of Cycad, with a comprehensive description of all the known species (as of 2012). At present (2015), the site is still running but is no longer being updated

Range

Southeast Asia - Myanmar, Thailand, Cambodia, Laos, Vietnam.

Habitat

Dry forests on limestone hills[
310
Title
Plant Resources of Southeast Asia
Publication
 
Author
 
Website
http://proseanet.org/
Publisher
 
Year
0
ISBN
 
Description
Lots of information on the uses of the plants of SE Asia.
]. Full sun to light shade in low open woodland on flat country or low hills, often in dense stands. Woodland is often dominated by Dipterocarpus tuberculatus with associated trees such as Erythrina and Bombax[
990
Title
The Cycad Pages
Publication
 
Author
 
Website
http://plantnet.rbgsyd.nsw.gov.au/PlantNet/cycad/wlist.html
Publisher
Royal Botanic Gardens, Sydney.
Year
2012
ISBN
 
Description
A website dedicated to the various species of Cycad, with a comprehensive description of all the known species (as of 2012). At present (2015), the site is still running but is no longer being updated
].

Properties

Conservation StatusVulnerable
Edibility Rating *  *
Medicinal Rating *  *
Other Uses Rating *  *
HabitDeciduous Shrub
Height1.50 m
Growth RateSlow
PollinatorsInsects
Self-fertileNo
Cultivation StatusOrnamental, Wild

Cultivation Details

A plant of tropical woodlands, growing in areas that are characteristically seasonally wet and dry with the monsoon weather patterns of the region, with particularly pronounced and extended dry periods[
990
Title
The Cycad Pages
Publication
 
Author
 
Website
http://plantnet.rbgsyd.nsw.gov.au/PlantNet/cycad/wlist.html
Publisher
Royal Botanic Gardens, Sydney.
Year
2012
ISBN
 
Description
A website dedicated to the various species of Cycad, with a comprehensive description of all the known species (as of 2012). At present (2015), the site is still running but is no longer being updated
].
This species is found in the wild in limestone-based soil among limestone boulders[
1935
Title
The Cycads
Publication
 
Author
Whitelock L.M.
Publisher
Timber Press; Portland, Oregon
Year
2002
ISBN
0-88192-522-5
Description
An excellent book dealing with the eleven different genera and almost 300 species of plants we know as Cycads. There are detailed descriptions and a host of other information for each species.
]. 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[
1935
Title
The Cycads
Publication
 
Author
Whitelock L.M.
Publisher
Timber Press; Portland, Oregon
Year
2002
ISBN
0-88192-522-5
Description
An excellent book dealing with the eleven different genera and almost 300 species of plants we know as Cycads. There are detailed descriptions and a host of other information for each species.
]. 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[
1935
Title
The Cycads
Publication
 
Author
Whitelock L.M.
Publisher
Timber Press; Portland, Oregon
Year
2002
ISBN
0-88192-522-5
Description
An excellent book dealing with the eleven different genera and almost 300 species of plants we know as Cycads. There are detailed descriptions and a host of other information for each species.
].
Unlike many species in the genus, this plant is completely deciduous, often being without leaves for some months (and often looking rather dead at this time), retaining the deciduous habit even in cultivation[
1935
Title
The Cycads
Publication
 
Author
Whitelock L.M.
Publisher
Timber Press; Portland, Oregon
Year
2002
ISBN
0-88192-522-5
Description
An excellent book dealing with the eleven different genera and almost 300 species of plants we know as Cycads. There are detailed descriptions and a host of other information for each species.
].
Unlike most other members of the genus, this species does not transplant easily. The best time to try 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[
1935
Title
The Cycads
Publication
 
Author
Whitelock L.M.
Publisher
Timber Press; Portland, Oregon
Year
2002
ISBN
0-88192-522-5
Description
An excellent book dealing with the eleven different genera and almost 300 species of plants we know as Cycads. There are detailed descriptions and a host of other information for each species.
].
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[
1935
Title
The Cycads
Publication
 
Author
Whitelock L.M.
Publisher
Timber Press; Portland, Oregon
Year
2002
ISBN
0-88192-522-5
Description
An excellent book dealing with the eleven different genera and almost 300 species of plants we know as Cycads. There are detailed descriptions and a host of other information for each species.
].
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[
1935
Title
The Cycads
Publication
 
Author
Whitelock L.M.
Publisher
Timber Press; Portland, Oregon
Year
2002
ISBN
0-88192-522-5
Description
An excellent book dealing with the eleven different genera and almost 300 species of plants we know as Cycads. There are detailed descriptions and a host of other information for each species.
]. 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[
1935
Title
The Cycads
Publication
 
Author
Whitelock L.M.
Publisher
Timber Press; Portland, Oregon
Year
2002
ISBN
0-88192-522-5
Description
An excellent book dealing with the eleven different genera and almost 300 species of plants we know as Cycads. There are detailed descriptions and a host of other information for each species.
].

Edible Uses

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

This species is said to have the same uses as Cycas rumphii. These uses are as follows:-
The pith is rich in carbohydrate and a sago can be made from it[
2
Title
Sturtevant's Edible Plants of the World.
Publication
 
Author
Hedrick. U. P.
Publisher
Dover Publications
Year
1972
ISBN
0-486-20459-6
Description
Lots of entries, quite a lot of information in most entries and references.
,
46
Title
Dictionary of Economic Plants.
Publication
 
Author
Uphof. J. C. Th.
Publisher
Weinheim
Year
1959
ISBN
-
Description
An excellent and very comprehensive guide but it only gives very short descriptions of the uses without any details of how to utilize the plants. Not for the casual reader.
,
61
Title
A Dictionary of Plants Used by Man.
Publication
 
Author
Usher. G.
Publisher
Constable
Year
1974
ISBN
0094579202
Description
Forget the sexist title, this is one of the best books on the subject. Lists a very extensive range of useful plants from around the world with very brief details of the uses. Not for the casual reader.
,
177
Title
Plants for Human Consumption.
Publication
 
Author
Kunkel. G.
Publisher
Koeltz Scientific Books
Year
1984
ISBN
3874292169
Description
An excellent book for the dedicated. A comprehensive listing of Latin names with a brief list of edible parts.
]. This use will kill the plant[
K
Title
Plants for a Future
Author
Ken Fern
Description
Notes from observations, tasting etc at Plants For A Future and on field trips.
].

The raw seed is poisonous, but after being cut into thin slices, dried, then steeped in water for a few minutes and dried again, it becomes edible[
2
Title
Sturtevant's Edible Plants of the World.
Publication
 
Author
Hedrick. U. P.
Publisher
Dover Publications
Year
1972
ISBN
0-486-20459-6
Description
Lots of entries, quite a lot of information in most entries and references.
,
61
Title
A Dictionary of Plants Used by Man.
Publication
 
Author
Usher. G.
Publisher
Constable
Year
1974
ISBN
0094579202
Description
Forget the sexist title, this is one of the best books on the subject. Lists a very extensive range of useful plants from around the world with very brief details of the uses. Not for the casual reader.
,
63
Title
Nuts.
Publication
 
Author
Howes. F. N.
Publisher
Faber
Year
1948
ISBN
-
Description
Rather old but still a masterpiece. Has sections on tropical and temperate plants with edible nuts plus a section on nut plants in Britain. Very readable.
,
146
Title
A Manual of Indian Timbers.
Publication
 
Author
Gamble. J. S.
Publisher
Bishen Singh Mahendra Pal Singh
Year
1972
ISBN
-
Description
First written in the 19th century, but still a classic, giving a lot of information on the uses and habitats of Indian trees. Not for the casual reader.
,
177
Title
Plants for Human Consumption.
Publication
 
Author
Kunkel. G.
Publisher
Koeltz Scientific Books
Year
1984
ISBN
3874292169
Description
An excellent book for the dedicated. A comprehensive listing of Latin names with a brief list of edible parts.
]. It can be used as a sago[
2
Title
Sturtevant's Edible Plants of the World.
Publication
 
Author
Hedrick. U. P.
Publisher
Dover Publications
Year
1972
ISBN
0-486-20459-6
Description
Lots of entries, quite a lot of information in most entries and references.
,
335
Title
Perennial Edible Fruits of the Tropics : an Inventory
Publication
 
Author
Martin, F. W.; Campbell, C. W.; Rubertbe, R. M.
Publisher
U.S. Dept. of Agriculture, Agricultural Research Service
Year
1987
ISBN
 
Description
A booklet giving terse details of almost 300 species of edible fruits, plus regional lists of Botanical and Common names for over 2,500 less well-known edible fruits of the tropics.
]. Using the seed for food cannot be recommended, however. The globose to ovoid seeds of Cycas siamensis are 27 - 29mm long and 22 - 30mm in diameter[
1935
Title
The Cycads
Publication
 
Author
Whitelock L.M.
Publisher
Timber Press; Portland, Oregon
Year
2002
ISBN
0-88192-522-5
Description
An excellent book dealing with the eleven different genera and almost 300 species of plants we know as Cycads. There are detailed descriptions and a host of other information for each species.
].

The very young leaves are edible[
177
Title
Plants for Human Consumption.
Publication
 
Author
Kunkel. G.
Publisher
Koeltz Scientific Books
Year
1984
ISBN
3874292169
Description
An excellent book for the dedicated. A comprehensive listing of Latin names with a brief list of edible parts.
]. When around 30 - 40cm long, the young, not yet quite unfolded, succulent leaves are cooked and eaten as a vegetable[
317
Title
Mansfeld's Database of Agricultural and Horticultural Plants
Publication
 
Author
 
Website
http://mansfeld.ipk-gatersleben.de/pls/htmldb_pgrc/f?p=185:3:4292127278597336
Publisher
 
Year
0
ISBN
 
Description
Terse details of a huge range of useful plants.
,
1934
Title
Economic Botany of the Cycads
Publication
Econ Bot 12, 3-41 (1958)
Author
Thieret J.W.
Website
https://doi.org/10.1007/BF02863122
Publisher
 
Year
1958
ISBN
 
Description
 
].

The plant yields a gum[
64
Title
Vegetable Gums and Resins.
Publication
 
Author
Howes. F. N.
Publisher
Faber
Year
 
ISBN
81-88818-17-8
Description
A very good book dealing with the subject in a readable way.
,
146
Title
A Manual of Indian Timbers.
Publication
 
Author
Gamble. J. S.
Publisher
Bishen Singh Mahendra Pal Singh
Year
1972
ISBN
-
Description
First written in the 19th century, but still a classic, giving a lot of information on the uses and habitats of Indian trees. Not for the casual reader.
,
171
Title
Economic Botany.
Publication
 
Author
Hill. A. F.
Publisher
The Maple Press
Year
1952
ISBN
-
Description
Not very comprehensive, but it is quite readable and goes into some detail about the plants it does cover.
].

Medicinal

A gum obtained from the plant has been used medicinally, particularly as an agent that is said to produce rapid suppuration when applied to malignant ulcers. The gum also has the repute of being a good antidote for snake and insect bites[
1934
Title
Economic Botany of the Cycads
Publication
Econ Bot 12, 3-41 (1958)
Author
Thieret J.W.
Website
https://doi.org/10.1007/BF02863122
Publisher
 
Year
1958
ISBN
 
Description
 
].

This species is said to have the same uses as Cycas rumphii. These uses are as follows:-
The pollen is narcotic[
240
Title
Glossary of Indian Medicinal Plants (Including the Supplement).
Publication
 
Author
Chopra. R. N., Nayar. S. L. and Chopra. I. C.
Publisher
Council of Scientific and Industrial Research, New Delhi.
Year
1986
ISBN
-
Description
Very terse details of medicinal uses of plants with a wide range of references and details of research into the plants chemistry. Not for the casual reader.
].

The bark and the seeds are ground to a paste with oil and used as a poultice on sores and swellings[
240
Title
Glossary of Indian Medicinal Plants (Including the Supplement).
Publication
 
Author
Chopra. R. N., Nayar. S. L. and Chopra. I. C.
Publisher
Council of Scientific and Industrial Research, New Delhi.
Year
1986
ISBN
-
Description
Very terse details of medicinal uses of plants with a wide range of references and details of research into the plants chemistry. Not for the casual reader.
].

The juice of tender leaves is useful in the treatment of flatulence and vomiting[
240
Title
Glossary of Indian Medicinal Plants (Including the Supplement).
Publication
 
Author
Chopra. R. N., Nayar. S. L. and Chopra. I. C.
Publisher
Council of Scientific and Industrial Research, New Delhi.
Year
1986
ISBN
-
Description
Very terse details of medicinal uses of plants with a wide range of references and details of research into the plants chemistry. Not for the casual reader.
].

Other Uses

A gum exudes through wounds in the plant, especially from the megasporophylls, stems and leaves[
1934
Title
Economic Botany of the Cycads
Publication
Econ Bot 12, 3-41 (1958)
Author
Thieret J.W.
Website
https://doi.org/10.1007/BF02863122
Publisher
 
Year
1958
ISBN
 
Description
 
]. It is used medicinally and as an adhesive[
1934
Title
Economic Botany of the Cycads
Publication
Econ Bot 12, 3-41 (1958)
Author
Thieret J.W.
Website
https://doi.org/10.1007/BF02863122
Publisher
 
Year
1958
ISBN
 
Description
 
].
When placed in water, Cycas gum begins to swell almost immediately. By the end of several days, it expands to many times its original size and becomes so colourless and transparent that it cannot be seen in water but must be felt for with a rod[
1934
Title
Economic Botany of the Cycads
Publication
Econ Bot 12, 3-41 (1958)
Author
Thieret J.W.
Website
https://doi.org/10.1007/BF02863122
Publisher
 
Year
1958
ISBN
 
Description
 
]. Cycas gum has been likened in its properties to that of Sterculia setigera[
1934
Title
Economic Botany of the Cycads
Publication
Econ Bot 12, 3-41 (1958)
Author
Thieret J.W.
Website
https://doi.org/10.1007/BF02863122
Publisher
 
Year
1958
ISBN
 
Description
 
]

This species is said to have the same uses as Cycas rumphii. These uses are as follows:-
The bark sap is used as a glue[
339
Title
Agroforestry in the Pacific Islands: Systems for Sustainability
Publication
 
Author
W.C. Clarke and R.R. Thaman (Editors)
Website
http://www.unu.edu/unupress/unupbooks/80824e/80824E00.htm#Contents
Publisher
United Nations University Press, Tokyo
Year
1993
ISBN
92-808-0824-9
Description
The guide includes information on 100 species of plants for Agroforestry. It is also available on the web at the address given above.
].

The fruits are strung together to make children's toys or rattles[
339
Title
Agroforestry in the Pacific Islands: Systems for Sustainability
Publication
 
Author
W.C. Clarke and R.R. Thaman (Editors)
Website
http://www.unu.edu/unupress/unupbooks/80824e/80824E00.htm#Contents
Publisher
United Nations University Press, Tokyo
Year
1993
ISBN
92-808-0824-9
Description
The guide includes information on 100 species of plants for Agroforestry. It is also available on the web at the address given above.
].

Propagation

Seed - best sown in containers as soon as it is ripe. Stored seed should be pre-soaked for 24 hours in warm water prior to sowing. The seed should be sown 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[
164
Title
Growing from Seed. Volume 4.
Publication
 
Author
Bird. R. (Editor)
Publisher
Thompson and Morgan.
Year
1990
ISBN
-
Description
Very readable magazine with lots of information on propagation. A good article on Yuccas, one on Sagebrush (Artemesia spp) and another on Chaerophyllum bulbosum.
].
Division of suckers in the spring[
188
Title
The RHS Gardener's Encyclopedia of Plants and Flowers
Publication
 
Author
Brickell. C.
Publisher
Dorling Kindersley Publishers Ltd.
Year
1990
ISBN
0-86318-386-7
Description
Excellent range of photographs, some cultivation details but very little information on plant uses.
].
Cite as: Tropical Plants Database, Ken Fern. tropical.theferns.info. 2023-01-27. <tropical.theferns.info/viewtropical.php?id=Cycas+siamensis>

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