Biological Diversity 2003   



R. arnoldii
(1a) R. arnoldii

Kingdom: Plantae
Phylum: Anthophyta
Subphylum: Magnoliophyta

Class: Magnoliopsida
Order: Rafflesiales
Family: Rafflesiaceae
Genus: Rafflesia
Species include: arnoldii, priceii, keithii, tengku-adlinii

[See below for pictures of these and other species. All images (5a)]


R. cantleyi


R. gadutensis


R. hasseltii


R. keithii

 

The Genus Rafflesia

Introduction
Rafflesia is a genus of flowering plants that is made up of of 16 known species. The best known of these species is Rafflesia arnoldii, which has the distinction of being the world’s largest flower, reaching a diameter of about three feet. The genus Rafflesia gets its name from Sir Stamford Raffles, the founder of the British colony of Singapore. (1)

Distribution
The 16 known species of Rafflesia are found in the jungles of Southeast Asia. [See map below.] Sir Raffles first discovered it in Sumatra with his friend Dr. Joseph Arnold, after whom the largest of the species, R. arnoldii, is named. To date, the Rafflesia flowers have been found only in Indonesia - on the islands of Sumatra and Java - and Malaysia, in particular in the East Malaysian states of Sabah and Sarawak. (2)

Click on the square to see a close-up map of the area where Rafflesia are found
(3a)


Habitat
The Rafflesia can be found at altitudes of between 500 and 700 meters in the forests of Borneo (Malaysia), Sumatra and Java. In these tropical rainforests, the climate is continuously warm and humid, with humidity frequently reaching 100% at night. (3)

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(2a) R. arnoldii


 

 


These are pictures of the Malaysian rainforests where Rafflesia live
(4a)

Conservation StatuS

All of the known species of Rafflesia are threatened or endangered. It is a "Totally Protected Plant" by law in Sarawak, but elsewhere in Malaysia it is only safeguarded by laws when found in protected areas like National or State Parks.

Conservation Issues

Rafflesia is found in forests in the Malaysian states of Sabah and Sarawak. Seven out of fifteen species worldwide of Rafflesia can be found in Malaysia. (6) Because the Rafflesia flower is located in specific areas, and little is know about its methods for pollination and seed dispersal, it is difficult to find conservation methods. Residents in Malaysia are encouraged to save the flowers on their private property, and are encouraged to charge small entrance fees to see the flower. This little income goes a long way in conserving the flowers. In peninsular Malaysia, flower buds are sold as traditional medicines. These buds are seen as a sign of fertility, and are given to help mothers recover after birth. The over collection of these buds has not helped with conservation efforts, and has drastically reduced the number of Rafflesia in the wild. (7) All of these factors lead to decreasing numbers of Rafflesia. Many species of Rafflesia are vulnerable to deforestation and development, and as populations grow, Rafflesia becomes more threatened. In Sabah, the flower and host vine Tetrastigma are protected under the state's Wildlife Conservation Enactment of 1997. In 2002, 44 of 83 Rafflesia found in the area were outside of designated conservation places. The beginning stages of conservation call for finding, monitoring and protecting the flowers that appear. Conservationists are hoping that complete habitat protection will come, but there is no sign of complete habitat protection in the near future. (8)

Conservation Organizations

Malaysian Nature Society (http://www.mns.org.my)
The Malaysian Nature Society, founded in 1940, is the oldest scientific and non-government organization in Malaysia and is dedicated to nature conservation and appreciation.

WWF Malaysia (http://www.wwfmalaysia.org)
The Malaysian chapter of the World Wildlife Fund

 

Ever wondered what the view from inside a Rafflesia looks like? Click below to see.

(6a & 6b.)

Looking for some Rafflesia links? - check these out:

  1. Want to read an account of a Rafflesia sighting? Click HERE
  2. Found a Rafflesia? Want to identify it? Go HERE to find a key to the species.

Literature Cited

(1) Woodward, Susan. 29 October 1997. Rafflesia arnoldii.
http://www.radford.edu/~swoodwar/CLASSES/GEOG235/biomes/ rainforest/raffles.html
(8 April 2003)

(2) Signgapore Zoological Gardens. 2000. Plants of the Rainforest: Rafflesia

http://www.szgdocent.org/ff/f-praff.htm
(8 April 2003)

(3) WWF Malaysia. 2000. Going Going Gone!
http://www.wwfmalaysia.org/Features/spaces/ malaysianrainforest2.htm
(8 April 2003)

(4) Unknown Author. 2000. Rafflesia Arnoldi: Fragile Fantasy Flower.
http://bengkulu.wasantara.net.id/yahoo/wisata/bunga.html (8 April 2003)

(5) Barkman, Todd. Rafflesia Life History. http://unix.cc.wmich.edu/~tbarkman/rafflesia/Rafflesia.html
(8 April 2003)

(6)
WWF Malaysia. 2000. Rafflesia.
http://www.wwfmalaysia.org/features/ Beautybeast/Rafflesia.htm
(8 April 2003)

(7) WILDBORNEO.net. 2003. Rafflesia of the Rainforest, The World's Largest Flower
http://wildborneo.virtualave.net/main/Fea_rafflesia.html
(8 April 2003)

(8) Yoga, S.S. 2002. Sabah's Blosson of Hope: Blooming Rafflesia of Sabeh. http://www.arbec.com.my/rafflesia.htm
(8 April 2003)


R. kerrii


R. pricei


R. rochussenii


R. tengku-adlinii


R. tuan-mudae


R. novum


R. manillana


R. patma


R. micropylora

 

Physical characteristics
The Rafflesia body consists of thread like growths on the tissues of a Tetrastigma vine root, on which it is parasitic. The plant produces no leaves, stems or roots and does not contain chlorophyll. The Rafflesia can be seen only when it is ready to reproduce, when the parasitic growths on the vine form a lump that develop into a structure somewhat resembling a cabbage. This cabbage-like bud bursts through the host’s bark, and after about 9 months will open to reveal the massive 5-petaled flower, with stamens and pistils, which develops into a fruit with seeds. The flowers, which sit directly on the forest floor, are each either male or female (female flowers are particularly rare), can measure more than a meter across and weigh 10 kilograms. Most flowers in the genus give off and smell of rotting flesh, hence its local name of “corpse flower.” This smell attracts flies, which pollinate the plant. The center of the flowers contain numerous spikes whose function are unknown, and it also holds several gallons of nectar. The fruit produced is round and about 15 cm in diameter, with thousands of tiny seeds. (2)

Food and feeding
Rafflesia is totally dependant upon a vine called Tetrastigma, which is related to the grapevine. Lacking roots, leaves and stems, the Rafflesia are parasitic upon their host vines, draining nourishment from them. (4)

Reproduction

The visible part of the Rafflesia’s life cycle happens only when it is ready to reproduce. A tiny bud forms on the outside of the vine’s roots or stem, which develops over a period of about a year to a cabbage-like head that eventually opens to reveal the flower. Inside the flower is a spiked disk, to which either stigma or stamens are attached, depending on the sex of the plant. The odor of the plant attracts flies and beetles into the plant to pollinate it. (5) Pollination in Rafflesia is thought to be a rare occurrence due to several factors. Firstly, the flowers are unisex and for the most part are found only in proximity to same sex plants. In order to have successful reproduction, the insect pollinators have to visit both male and female plants, which not only are frequently not in close proximity to each other, but are also not necessarily mature and open at the same time. To complicate matters is the fact that the flowers last less than a week, leaving a narrow window of opportunity for pollination. (2)
The fruit produced by Rafflesia is round and about 15cm in diameter, filled with smooth flesh and thousands of tiny hard coated seeds. The flesh attracts squirrels and tree shrews which are thought to be the main distributors of the seeds. (6)
Click here for Rafflesia in different stages.


(7a)

Images Cited

1a. Gerhard Winter's Rafflesia site
http://www.senckenberg.uni-frankfurt.de/private/gwinter/rafl.htm

2a. Picture of Rafflsia arnoldii
http://www.fogato.com/modelli/mod_piante/rafflesia.html

3a. world map www.worldatlas.com

4a. http://www.wwfmalaysia.org/Features/spaces/ malaysianrainforest2.htm

5a. http://www.science.siu.edu/parasitic-plants/Rafflesiaceae/Rafflesia.gallery

6a. http://www.science.siu.edu/parasitic-plants/Rafflesiaceae/Raff.arn.page.html
6b. http://www.szgdocent.org/ff/f-praff.htm

7a. http://www.lostworldarts.com/asia/rafflesia3.htm

Background image: http://www.science.siu.edu/parasitic-plants/Rafflesiaceae/Raff.arn.page.html

Authors: Chris Nicholson (nichoch@earlham.edu)
and Beth Given (givenbe@earlham.edu)

Creation/revision date: 1st April 2003


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This website is part of a Biology 226 class project on the conservation of global biodiversity.

Earlham Biology Department Biology 226: Biological Diversity

Copyright -2003 Earlham College. Revised 28th March 2003. Send corrections or comments to mailto:givenbe@earlham.edu