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Notes in Botany Prepared by: Norberto R. Bautista

The Philippine Rafflesia: An Overview

Rafflesias are enigmatic group of parasitic flowering plants which deservesattention as it is unique, intriguing, and at the same time endangered. Theirsurvival will depend on how we take care of our forest. It is a plant not intendedfor the home garden, however, it will be a very popular plant to attract foreigntourists in a botanical garden. The plant has no stems, leaves nor true roots, which makes it a strange or weirdplant, right? It is an endoparasite of a specific plant host, the Tetrastigma vinewhich belongs to the Vitaceae or grape family. The Tetrastigma vine is its onlyhost, thus, theoretically, if you want to grow Rafflesia, you have to grow theTetrastigma vine first through stem cuttings, and introduce the seeds later. TheRafflesia spreads its root-like haustoria inside the tissues of the vine, andabsorbs its host’s sap until it matures. The only part of the plant that can be seenoutside the host vine is the five-petaled flower, range in size from 3 feet wide to 6inches in diameter.

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An Indonesian guide working for Dr. Joseph Arnold in 1818 discovered the firstRafflesia plant in the rain forest of Indonesia. The plant was named after SirThomas Stamford Raffles, the leader of the expedition. The genus contains approximately 27 species all found in southeastern Asia, onthe Malay Peninsula, Borneo, Sumatra, and the Philippines. The Philippines has9 species namely: R. schandenbergiana (2nd largest in the world, and the largestin the Philippines), R. speciosa, R. panchoana, R. mira, R. manillana (thesmallest), R. lobata, R. leonardi, R. banahawensis and R. baletei. Our country isthe center of Rafflesia research. The plant group belongs to the mysterious Rafflesiaceae family. With the adventof DNA tests, it was revealed that comparing the mitochondrial DNA (mtDNA)sequences of Rafflesia with other angiosperm (flowering plants), it was indicatedthat this parasite evolved from photosynthetic plants of the order Malpighiales and is closely related to the family Euphorbiaceae (where your Poinsettia andEuphobia plants belong), which is astonishing as members of that family typicallyhave very small flowers. The Rafflesia plants are considered the "Queens of the Parasites," as onespecies, Rafflesia arnoldii (the largest of its kind and is found in Indonesia), hasenormous three-foot wide, waxy-looking red and white-freckled blossoms whichsmell like rotting corpse. The flowers’ smell gave the plant its local names whichtranslate 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 orblue bottle flies, which transport pollen from male to female flowers. Little isknown about the plant’s seed dispersal. However, tree shrews, rodents and otherforest mammals apparently eat the fruits and disperse the seeds. Rafflesia is anofficial 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 inSoutheast Asia. The Rafflesia shares its characteristic corpse-smelling flowers to the PungapungArum plant (Amorphophallus titanum) of the Araceae family. Both Rafflesia andAmorphophallus are flowering plants, but they are distantly related. Even though it has a very attractive looking flower, there has been no technologyyet to cultivate the plant in gardens or in greenhouses. It relies primarily to itshost, the Tetrastigma vine, in order for the plant to live. Thus, research has beenbeing done in order to grow the Tetrastigma vine and then to inoculate theRafflesia plant into it.

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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 inremote Malaysian, Indonesian and Philippine rain forests. The life cycle of this plant is still an enigma. People tend to see the plant onlywhen it flowers, and it is found only in a specific location. Thus, there is a needto protect sites where the plant is found, or else, the plant disappears when itsforest 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, Rafflesiamay be the "giant panda of the plant world." Though a single female flower mayproduce thousands of seeds, and likely dispersed by tree shrews, rats and otherwildlife, 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 toattract tourists, and protects specific sites where the plants grow. We hope tosee a horticultural technology be developed to cultivate and propagate Rafflesiain botanical gardens or greenhouses in the Philippines. Philippine species Filipino scientists and botanists has been tremendously active since 2002 indiscovering and naming several new species of Rafflesia. Before this time therewere only two species known: R. manillana and R. schadenbergiana, the latter ofwhich was last seen in 1882 on Mt. Apo in Davao Province, Mindanao and wasthought to be extinct.

Rafflesia schadenbergiana Rafflesia manillana

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Rafflesia lobota (left) and Rafflesiaspeciosa (upper right) both smallsized Rafflesias.

However, in 2002 Dr. Julie Barcelona and Dr. Edwino Fernando discoveredRafflesia speciosa in the mountains of Antique Province. Three years after, in2005, another Rafflesia was Dr. Fernando and Dr. Perry Ong on the remote Mt.Candalaga, Maragusan, Campostela Valley Province on Mindanao. It wasnamed Rafflesia mira.

Rafflesia mira Rafflesia panchoana

Another group (that of Dr. Domingo Madulid and his co-workers publishedanother name (R. magnifica) later, however, R. mira stands as thenomenclaturally valid name. R. mira (45-60 cm in diameter), is approximately thesame size as R. speciosa (45-56 cm) of Antique Province, but definitely largerthan Luzon’s R. manillana (14-20 cm in diameter).

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In April 2005, during his expedition to Mt. Igtuog and Mt. Sakpaw in the CentralPanay 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 1991from 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 hasconfirmed it to be different from R. manillana. Several new populations have alsobeen seen in the Camarines Sur Province, specifically in Mt. Isarog and Mt. Asog(or Mt. Iriga).

Rafflesia baletei Rafflesia banahawensis

Moreover, in 2007, Dr. Julie Barcelona reports on the discovery of yet anotherpopulation of the rare R. schandenbergiana in Bukidnon. In the same year, a new Rafflesia species was discovered in Mt. Banahaw inLuzon, a popular destination for mountaineering and religious groups. It is anunlikely spot to find a new species of this strange plant. But such was the caseand two papers was published naming it R. banahawensis by Dr. Madulid andanother by the group of Dr. Barcelona Dr. Madulid and co-workers also discovered on the same year (but published in2008), through additional field and herbarium work on the Rafflesia knownoriginally as R. manillana from Mt. Makiling yielded the description of a newspecies, R. panchoana.

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Comparative sizes of flowers of Rafflesia species and their habitat location.

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In 2008, in the remote sitio Kinapawan in the coastal town of Lallo in CagayanValley, a new Rafflesia was made known to Filipino botanists. Working withCAVAPPED, Conservation International (CI), and DENR staff, Dr. Barcelonatraveled 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 issimilar to R. manillana of Samar and Luzon and R. lobata of Panay by the widediaphragm aperture and flowers that grow on the roots and aerial portion of thevine. It is, however, different in its larger size (to 34 cm), central disk that isnearly smooth or with markedly reduced processes, and the absence of whiteblotches/windows inside the floral tube. It is the 5th Rafflesia found on Luzonand the 9th from the Philippines.

Horticultural techniques in growing this uniquely Philippine group of plants is stillbeing studied. An advocacy in indigenous and endemic flora appreciation andeducation, protection and conservation of our last remaining forest is beingspearheaded by the Philippine Native Plant Conservation Society, Inc (PNPCSI),in which it was initiated & founded by Mr. Leonardo L. Co & Dr. Julie Barcelona in2008. It is a group of active botanists, horticulturists and plant enthusiasts whichmakes plant growing and identification their passion. The Rafflesia is part oftheir society’s logo.

A Filipino child beside a Rafflesia schandenbergiana, the largest PhilippineRafflesia