The Weirdest of the Weird May 14, 2009
(Photos by Dr. Julie Barcelona)
Rafflesias are enigmatic group of parasitic flowering plants which deserves attention as it is unique, intriguing, and at the same time endangered. Their survival will depend on how we take care of our forest. It is a plant not intended for the home garden, however, it will be a very popular plant to attract foreign tourists in a botanical garden.
The plant has no stems, leaves or true roots. Strange, right? It is an endoparasite of a specific plant host, the Tetrastigma vine which belongs to the Vitaceae or grape family. The Tetrastigma vine is its only host, thus, theoretically, if you want to grow Rafflesia, you have to grow the Tetrastigma vine first through stem cuttings, and introduce the seeds later. The Rafflesia spreads its root-like haustoria inside the tissues of the vine, and absorbs its host’s sap until it matures. The only part of the plant that can be seen outside the host vine is the five-petaled flower, range in size from 3 feet wide to 6 inches in diameter.
An Indonesian guide working for Dr. Joseph Arnold in 1818 discovered the first Rafflesia plant in the rain forest of Indonesia. The plant was named after Sir Thomas Stamford Raffles, the leader of the expedition.
The genus contains approximately 27 species all found in southeastern Asia, on the Malay Peninsula, Borneo, Sumatra, and the Philippines. The Philippines has 9 species namely: R. schandenbergiana (2nd largest in the world, and the largest in the Philippines), R. speciosa, R. panchoana, R. mira, R. manillana (the smallest), R. lobata, R. leonardi, R. banahawensis and R. baletei. Our country is the center of Rafflesia research. The plant group belongs to the mysterious Rafflesiaceae family. With the advent of DNA tests, it was revealed that comparing the mitochondrial DNA (mtDNA) sequences of Rafflesia with other angiosperm (flowering plants), it was indicated that this parasite evolved from photosynthetic plants of the order Malpighiales and is closely related to the family Euphorbiaceae (where your Poinsettia and Euphobia plants belong), which is astonishing as members of that family typically have very small flowers.
The Rafflesia plants are considered the “Queens of the Parasites,” as one species, Rafflesia arnoldii (the largest of its kind and is found in Indonesia), has enormous three-foot wide, waxy-looking red and white- freckled blossoms which smell like rotting corpse. The flowers’ smell gave the plant its local names which translate to “corpse flower” or “meat flower”.
Yet not all Rafflesia blooms are monster-sized. Some produce only smaller, palm-sized blossoms. The smallest, R. manillana, has 20 cm diameter flowers.
The vile smell that the flower gives off attracts insects such as carrion flies or blue bottle flies, which transport pollen from male to female flowers. Little is known about the plant’s seed dispersal. However, tree shrews, rodents and other forest mammals apparently eat the fruits and disperse the seeds. Rafflesia is an official state flower of Sabah in Malaysia, as well as for the Surat Thani Province, Thailand. The Rafflesia flower is the icon of plant conservation works in Southeast Asia.
The Rafflesia shares its characteristic corpse-smelling flowers to the Pungapung Arum plant (Amorphophallus titanum) of the Araceae family. Both Rafflesia and Amorphophallus are flowering plants, but they are distantly related.
Even though it has a very attractive looking flower, there has been no technology yet to cultivate the plant in gardens or in greenhouses. It relies primarily to its host, the Tetrastigma vine, in order for the plant to live. Thus, research has been being done in order to grow the Tetrastigma vine and then to inoculate the Rafflesia plant into it.
Most folks never get to see this plant in bloom as the Rafflesia rarely blossom, sometimes taking five to 10 years between flowerings. And they’re found only in remote Malaysian, Indonesian and Philippine rain forests.
The life cycle of this plant is still an enigma. People tend to see the plant only when it flowers, and it is found only in a specific location. Thus, there is a need to protect sites where the plant is found, or else, the plant disappears when its forest site is destroyed and converted into agricultural land.
Rafflesia blooms usually in the rainy season, and begin to senesce in a few days, turning to slimy, black masses. A phenomenon in the plant kingdom, Rafflesia may be the “giant panda of the plant world.” Though a single female flower may produce thousands of seeds, and likely dispersed by tree shrews, rats and other wildlife, but their survival is still in question. Seeds rarely find host vines, thus, elevating their unpredictable flowerings.
Malaysian and Indonesian botanical gardens usually use Rafflesia species to tourists, and protect specific sites where the plants grow. We hope to see a horticultural technology be develop to cultivate and propagate Rafflesia in botanical gardens or greenhouses in the Philippines.
Philippine Rafflesia species
Filipino scientists and botanists has been tremendously active since 2002 in discovering and naming several new species of Rafflesia. Before this time there were only two species known: R. manillana and R. schadenbergiana, the latter of which was last seen in 1882 on Mt. Apo in Davao Province, Mindanao and was thought to be extinct.
However, in 2002 Dr. Julie Barcelona and Dr. Edwino Fernando discovered Rafflesia speciosa in the mountains of Antique Province. Three years after, in 2005, another Rafflesia was Dr. Fernando and Dr. Perry Ong on the remote Mt. Candalaga, Maragusan, Campostela Valley Province on Mindanao. It was named Rafflesia mira.
Another group (that of Dr. Domingo Madulid and his co-workers published another name (R. magnifica) later, however, R. mira stands as the nomenclaturally valid name. R. mira (45-60 cm in diameter), is approximately the same size as R. speciosa (45-56 cm) of Antique Province, but definitely larger than Luzon’s R. manillana (14-20 cm in diameter).
In April 2005, during his expedition to Mt. Igtuog and Mt. Sakpaw in the Central Panay mountain range, Renee Galang discovered a previously undescribed Rafflesia which was later named R. lobata by Galang and Madulid in 2006.
In 2006, a previously collected and undescribed species by Danny Balete in 1991 from the Bicol Region was recognized. Dr. Barcelona, Mary Ann Cajano and Dr. Annalee Hadsall named it R. baletei in honor of its discoverer after field work has confirmed it to be different from R. manillana. Several new populations have also been seen in the Camarines Sur Province, specifically in Mt. Isarog and Mt. Asog (or Mt. Iriga).
Moreover, in 2007, Dr. Julie Barcelona reports on the discovery of yet another population of the rare R. schandenbergiana in Bukidnon.
In the same year, a new Rafflesia species was discovered in Mt. Banahaw in Luzon, a popular destination for mountaineering and religious groups. It is an unlikely spot to find a new species of this strange plant. But such was the case and two papers was published naming it R. banahawensis by Dr. Madulid and another by the group of Dr. Barcelona
Dr. Madulid and co-workers also discovered on the same year (but published in 2008), through additional field and herbarium work on the Rafflesia known originally as R. manillana from Mt. Makiling yielded the description of a new species, R. panchoana.
In 2008, in the remote sitio Kinapawan in the coastal town of Lallo in Cagayan Valley, a new Rafflesia was made known to Filipino botanists. Working with CAVAPPED, Conservation International (CI), and DENR staff, Dr. Barcelona traveled to the site and collected the type of this Rafflesia. She named it R. leonardi, in honor of Leonardo Co, who is an expert on the Cagayan Flora. It is similar to R. manillana of Samar and Luzon and R. lobata of Panay by the wide diaphragm aperture and flowers that grow on the roots and aerial portion of the vine. It is, however, different in its larger size (to 34 cm), central disk that is nearly smooth or with markedly reduced processes, and the absence of white blotches/windows inside the floral tube. It is the 5th Rafflesia found on Luzon and the 9th from the Philippines.
An advocacy in protecting and conserving our last remaining forest is being spearheaded by the Philippine Native Plant Conservation Society, Inc (PNPCSI).
Interested individuals who would like to contact this wonderful group can get in touch with our president, Mr. Leonardo Co. Our Headquarters are located at Cottage No. 2, Ninoy Aquino Parks and Wildlife Center, Department of Environment & Natural Resources, North Avenue corner Elliptical Road, Diliman, Quezon City.
Ref.: http://philippinerafflesia.wordpress.com/
Look also here: www.flora.aboutphilippines.ph