
Cycas revoluta
Cycas revoluta
Safety & Hazards
The plants contain alkaloids of carcinogens and also an amino-acid that causes chronic nervous disorders[1]. 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.
Cultivation Details
Cycas revoluta is probably the hardiest cycad, able to tolerate light frosts, with reports of plants withstanding temperatures as low as -6°c[2, 3]. It can be grown from the warm temperate zone through to the tropics[2]. Requires a sunny position[4]. Plants are sometimes found in dense shade in the wild[5]. Requires a strong loam with sharp sand and good drainage[6]. Succeeds in dry soils. Plants are tolerant of saline conditions[3]. Plants are very slow growing[4, 7]. 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[1]. Overall its use is not to be recommended, especially since it is becoming rare in the wild. 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[3]. 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[3]. 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[3]. 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[3].
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[6]. Pre-soak stored seed for 24 hours in warm water then treat as above. Division of suckers in the spring. Cite as: Temperate Plants Database, Ken Fern. temperate.theferns.info. 2026-02-21. <temperate.theferns.info/plant/Cycas+revoluta>
Pollinators
Insects, wind
References
- [1]The New RHS Dictionary of Gardening. 1992. — Huxley. A. · MacMillan Press · 1992 · ISBN 0-333-47494-5 ↩︎Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed.
- [2]Palm and Cycad Societies of Australia. — http://www.pacsoa.org.au/ ↩︎Contains at least a little information on the majority of palm and cycad species, plus a wealth of photographs. A first class website.
- [3]The Cycads — Whitelock L.M. · Timber Press; Portland, Oregon · 2002 · ISBN 0-88192-522-5 ↩︎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.
- [4]The RHS Gardener's Encyclopedia of Plants and Flowers — Brickell. C. · Dorling Kindersley Publishers Ltd. · 1990 · ISBN 0-86318-386-7 ↩︎Excellent range of photographs, some cultivation details but very little information on plant uses.
- [5]IUCN Red List of Threatened Species — http://www.iucnredlist.org/ ↩︎A list of plants under threat and facing possible extinction, usually with brief details of the threats and information on habitat.
- [6]Growing from Seed. Volume 4. — Bird. R. (Editor) · Thompson and Morgan. · 1990 · ISBN - ↩︎Very readable magazine with lots of information on propagation. A good article on Yuccas, one on Sagebrush (Artemesia spp) and another on Chaerophyllum bulbosum.
- [7]Conservatory and Indoor Plants Volumes 1 & 2 — Phillips. R. & Rix. M. · Pan Books, London. · 1998 · ISBN 0-330-37376-5 ↩︎Excellent photos of over 1,100 species and cultivars with habits and cultivation details plus a few plant uses. Many species are too tender for outdoors in Britain though there are many that can be grown outside.
- [8]Mansfeld's Database of Agricultural and Horticultural Plants — http://mansfeld.ipk-gatersleben.de/pls/htmldb_pgrc/f?p=185:3:4292127278597336 ↩︎Terse details of a huge range of useful plants.
- [9]Economic Botany of the Cycads — Thieret J.W. · 1958 · https://doi.org/10.1007/BF02863122 ↩︎
- [10]Flora of Japan. (English translation) — Ohwi. G. · Smithsonian Institution · 1965 · ISBN - ↩︎The standard work. Brilliant, but not for the casual reader.
- [11]Flora of China — Missouri Botanical Garden Press; St. Louis. · 1994 · http://flora.huh.harvard.edu/china/ ↩︎An excellent, comprehensive resource in 25 volumes. In addition to the botanical information the flora also gives basic information on habitat and some uses. An on-line version is also available.
- [12]The Cycad Pages — Royal Botanic Gardens, Sydney. · 2012 · http://plantnet.rbgsyd.nsw.gov.au/PlantNet/cycad/wlist.html ↩︎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
- [13]Sturtevant's Edible Plants of the World. — Hedrick. U. P. · Dover Publications · 1972 · ISBN 0-486-20459-6 ↩︎Lots of entries, quite a lot of information in most entries and references.
- [14]Dictionary of Economic Plants. — Uphof. J. C. Th. · Weinheim · 1959 · ISBN - ↩︎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.
- [15]Plants for Human Consumption. — Kunkel. G. · Koeltz Scientific Books · 1984 · ISBN 3874292169 ↩︎An excellent book for the dedicated. A comprehensive listing of Latin names with a brief list of edible parts.
- [16]Cornucopia - A Source Book of Edible Plants. — Facciola. S. · Kampong Publications · 1990 · ISBN 0-9628087-0-9 ↩︎Excellent. Contains a very wide range of conventional and unconventional food plants (including tropical) and where they can be obtained (mainly N. American nurseries but also research institutes and a lot of other nurseries from around the world.
- [17]Medicinal Plants of China — Duke. J. A. and Ayensu. E. S. · Reference Publications, Inc. · 1985 · ISBN 0-917256-20-4 ↩︎Details of over 1,200 medicinal plants of China and brief details of their uses. Often includes an analysis, or at least a list of constituents. Heavy going if you are not into the subject.
- [18]CosIng — http://ec.europa.eu/growth/tools-databases/cosing/ ↩︎CosIng is the European Commission database for information on cosmetic substances and ingredients.