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Rafflesia Kerrii

During a visit to Khao Sok Lake in 2007 while onboard a long-tail boat, somebody mentioned the flower Rafflesia or "bua-pòot" ( บัวผุด ) in Thai. Quickly came to my mind Attenborough's BBC series and his passionate narratives. At that time, this was the only reference I had about this flower, and I am grateful that it was through these series of nature I came to know about it because Attenborough’s enthusiasm can indeed, be very contagious.

Kingdom:  Plantae
Division: Magnoliophyta
Class:    Magnoliopsida
Order:    Malpighiales
Family:   Rafflesiaceae
Genus:    Rafflesia

A more recent DNA study (2007) found Rafflesia and its relatives to be embedded within the family Euphorbiaceae, which is surprising as members of that family typically have very small flowers.

Thai name: บัวผุด ( bua-pòot )

The Rafflesia kerrii, like all other members of the genus Rafflesia, is a most interesting plant, and admiration is shared by both the botanist and the general public. The news, at least for Europe, was first communicated in 1818, in a letter by Sir Thomas Stamford Raffles to the then president of the Royal Society, Sir Joseph Banks. Everything began when an Indonesian guide reported the flower (Rafflesia arnoldii) to Dr Joseph Arnold. The following is an extract from a letter written by Dr. Arnold to one of his friends:

 

Here (at Pulo Lebbar, on the Manna River, two days' journey inland of Manna) I rejoice to tell you I happened to meet with what I consider as the greatest prodigy of the vegetable world. I had ventured some way from the party, when one of the Malay servants came running to me with wonder in his eyes, and said, "Come with me, Sir, come! a flower, very large, beautiful, wonderful!"

Rafflesias are parasitical flowering plants and since flower production is an expensive business for plants, one could maybe explain Rafflesia’s extravagancy in size. They do not posses leaves, stems or roots, and they don't photosynthesize. There are vestiges of leaves in some species in the form of scales. They parasitize a vine from the genus Tetrastigma of the grape family found in the forested mountains of Southeast Asian region.

Surface structure of one of the five lobes of Rafflesia kerrii

Surface structure of one of the five lobes of Rafflesia kerrii.

 

After a long stage of germination, the first visible sign of the flower is a small nodule / nob in the surface of the host’s root. Then, under a period of approximately eight months, the flower or protuberance at this stage, grows up to the size of a medium ball around 20 cm in diameter. Our jungle guide told us that when the opening take’s place, you can sometimes hear a “pop”, probably caused by the vacuum.

Rafflesia kerrii bud on the root of the vine.

Rafflesia kerrii bud on the root of the vine.

 

 

 

 

 

During the few days it has left after the bloom, usually 6 to 7 days, the flower has to catch the attention of the pollen delivery service, the carrion flies. With luck, another site in bloom of the opposite sex will be nearby. Then, and only then, the pollination will take place. The fruit produced is a kind of small berry, containing sticky seeds thought to be disseminated by tree shrews and other rodents.

Amazing that they manage to reproduce against all odds!

Detail of the windows inside the chamber. Rafflesia kerrii

Detail of Windows on the inner side of the diaphragm.

 

 

Rafflesia arnoldii on the root of a Tetrastigma vine. The location of the sexual parts are indicated by the arrow. (Drawing by Meijer 1958)

Rafflesia arnoldii on the root of a Tetrastigma vine. The location of the sexual parts are indicated by the arrow. (Drawing by Meijer 1958)

 

 

 

 

 

 

 

 

 

 

 

 

 

Given that Rafflesia flowers last so little, preparation is highly recommended. More so, if you are only interested in them. Otherwise, any trekking in Thailand’s rain forest, with or without Rafflesia, is a pleasure for anybody interested in nature. That said, where to look is not sufficient, you want to ensure that you get there during the bloom. Some of those sites are very difficult to reach and you do not want to arrive at your destination only to be received by rotten flowers.

Rotten Rafflesia kerrii

Rotten Rafflesia kerrii.

 

 

 

 

 

 

 

 

Luckily, we knew some sites and Tid, with his vast contact network, got a positive confirmation after a few phone calls. Two days ago, someone saw fresh open ones in a remote location. That day we finished with a good hot “kêe lèk” ( ขี้เหล็ก ) and cold beers.

 

Close-up of the processes inside the perigone tube. Rafflesia kerrii.

Processes inside the chamber of the perianth cup serving as heat dissipators. Rafflesia kerrii.

 

 

 

 

 

 

 

 

 

 

 

A long walk was ahead of us, so we started early in the morning with our new addition to the team, the jungle guide. We had some heavy rains the day before our journey, making the terrain extremely slippery. Finally, after a few hours of struggling with nature, we arrived to our destination. After our meal, kindly prepared by a local family at the base of the mountain, we started taking pictures and inspecting the flowers. I highly recommend a flash, since it can get very dark inside the jungle.

Tid inspecting a Rafflesia kerrii

Tid inspecting a Rafflesia kerrii

 

 

 

 

 

 

 

 

 

 

Diaphragm of the Rafflesia kerrii

Diaphragm of the Rafflesia kerrii.

 

 

 

 

 

 

 

 

 

 

There are concerns about the harmful impact that tourism can have on these parasitical plants. What we witnessed here at Khao Sok, might be and example for other sites. We received detailed instructions from the jungle guide as how to manoeuvre around the flowers and things to watch for. Since Rafflesia sightseeing has become a source of income for the locals, they take great care in preserving them. Also, most of those sites, besides being almost impossible to reach without a guide because their isolated location, are inside reservations. All this might not be the case elsewhere, and the most significant threat to the Rafflesia is, of course, the destruction of its rainforest. Let us hope that at least here, the situation remains unchanged.

- Pictures from this article can also be seen in the Gallery section.


References:
- Companion to the Botanical Magazine Vol.1 1835
- Nature and Art Vol.1 1866
- Encyclopaedia Britannica 15th Edition 1978
- Davis, C. C.; M. Latvis, D. L. Nickrent, K. J. Wurdack, D. A. Baum (January 11, 2007). "Floral gigantism in Rafflesiaceae"
- Wikipedia