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Cycas rumphii
Cycadaceae FAMILY Near Threatened

Cycas rumphii

Cycas rumphii

Edibility
2/5
Medicinal
2/5

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

HabitEvergreen Shrub
GrowthSlow

Succeeds in the hot tropics and subtropics[2]. Plants are tolerant of light frost[2]. Although Cycads 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[3]. Prefers a sunny position, but also succeeds in light shade[4, 5]. Requires a strong loam with sharp sand and good drainage[6]. Succeeds in dry soils. Succeeds in poor soils[5]. The seeds float and can be transported long distances in the sea, thus accounting for the very large distribution of this species[7]. Plants are slow-growing[4]. 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

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[3]. 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[3]. Cite as: Tropical Plants Database, Ken Fern. tropical.theferns.info. 2026-02-20. <tropical.theferns.info/viewtropical.php?id=Cycas+rumphii>

Pollinators

Insects, wind

References

  1. [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. [2]Perennial Edible Fruits of the Tropics : an Inventory — Martin, F. W.; Campbell, C. W.; Rubertbe, R. M. · U.S. Dept. of Agriculture, Agricultural Research Service · 1987 ↩︎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.
  3. [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. [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. [5]Tropical Ornamentals; A Guide — Whistler. W. Arthur. · Timber Press Inc. Oregon. · 2000 · ISBN 0-88192-448-2 ↩︎An excellent little guide to some of the more commonly cultivated ornamental plants of the Tropics, often giving some information on the plants other uses.
  6. [6]RHS Dictionary of Plants plus Supplement. 1956 — F. Chittendon. · Oxford University Press · 1951 · ISBN - ↩︎Comprehensive listing of species and how to grow them. Somewhat outdated, it has been replaced in 1992 by a new dictionary (see [ 200 ]).
  7. [7]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.
  8. [8]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.
  9. [9]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.
  10. [10]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.
  11. [11]A Dictionary of Plants Used by Man. — Usher. G. · Constable · 1974 · ISBN 0094579202 ↩︎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.
  12. [12]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.
  13. [13]Economic Botany of the Cycads — Thieret J.W. · 1958 · https://doi.org/10.1007/BF02863122 ↩︎
  14. [14]Nuts. — Howes. F. N. · Faber · 1948 · ISBN - ↩︎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.
  15. [15]A Manual of Indian Timbers. — Gamble. J. S. · Bishen Singh Mahendra Pal Singh · 1972 · ISBN - ↩︎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.
  16. [16]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
  17. [17]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.
  18. [18]Vegetable Gums and Resins. — Howes. F. N. · Faber · ISBN 81-88818-17-8 ↩︎A very good book dealing with the subject in a readable way.
  19. [19]Economic Botany. — Hill. A. F. · The Maple Press · 1952 · ISBN - ↩︎Not very comprehensive, but it is quite readable and goes into some detail about the plants it does cover.
  20. [20]Glossary of Indian Medicinal Plants (Including the Supplement). — Chopra. R. N., Nayar. S. L. and Chopra. I. C. · Council of Scientific and Industrial Research, New Delhi. · 1986 · ISBN - ↩︎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.
  21. [21]Agroforestry in the Pacific Islands: Systems for Sustainability — W.C. Clarke and R.R. Thaman (Editors) · United Nations University Press, Tokyo · 1993 · http://www.unu.edu/unupress/unupbooks/80824e/80824E00.htm#Contents · ISBN 92-808-0824-9 ↩︎The guide includes information on 100 species of plants for Agroforestry. It is also available on the web at the address given above.