The Rafflesia, the world’s largest flower, is a parasitic plant found only in Southeast Asia, and then only in sub-mountainous hilly forests at elevations between 400-1,300 metres.
Sir Stamford Raffles and Dr Joseph Arnold were the first Europeans to discover the Rafflesia. In 1818, whilst on a field trip near the town of Bencoolen (Bengkulu) in Sumatra, they came across a huge specimen that measured 97 cm in diameter. This species was later named the Rafflesia Arnoldi. When news of the discovery reached the botanical community in 1820 it caused quite a sensation with murmurings of disbelief.
There are thought to be 17 species of Rafflesia, some of which may already be extinct. Three species are found in Sarawak – the Rafflesia Pricei, Rafflesia Arnoldi and Rafflesia Tuan-Mudae, which is actually a type of Arnoldi. Only one species, Rafflesia Tuan-Mudae, is found at Gunung Gading.
The Rafflesia is as unusual as it is spectacular. Much of the flower’s biology remains a mystery to this day. It has no specific flowering season and it has no roots, leaves or stem. The Rafflesia depends on a host vine – the tetrastigma, a member of the grape family. Scientists are still unsure why the Rafflesia associates itself with the tetrastigma vine or how the seeds of a Rafflesia germinate and grow. What is known is that threads of tissue spread out within the vine and absorb nutrients. After 18 months a small dark brown bud appears.
Such a long period of growth means that there is a high risk of damage; even when a bud forms there is no guarantee that it will mature into a Rafflesia flower. A bud takes nine months to mature, when it may measure up to 16 cm in diameter, and studies have shown that a high percentage of buds do not survive, as they are susceptible to both drought and heavy rain.
After nine months the brown ‘leaves’ of the cabbage-like bud open, revealing the underside of the petal-like lobes. It takes several hours for a flower to open fully. There are usually five thick and fleshy red-coloured petals, covered in lighter coloured spots, warts and blotches. The Rafflesia only blooms for 3-5 days, before it starts to blacken and rot. Although it is quite common for a number of buds to occur in a cluster at the same site, it is rare for two plants of the same cluster to bloom at the same time.
Rafflesia flowers are either male or female, and therefore cannot self-pollinate. For pollination to take place, a male and a female flower must bloom at the same time and pollen must be transported over considerable distances. In the Rafflesia’s case pollination is carried out by carrion flies, so whilst in full bloom the Rafflesia gives off a foul smell of decaying flesh to attract them. Seeds are thought to be dispersed by rodents and other small mammals which eat the flowers. Scientists remain baffled, however, as to how the tiny seeds infest the roots and stems of the host vine.
Loss of habitat is the greatest threat to the survival of the Rafflesia. Its reliance on the tetrastigma vine does not help matters. With other endangered species it is possible to implement a range of conservation measures such as trans-location and the establishment of nurseries. However, these measures are not possible with the Rafflesia due to its very high degree of specialization. The establishment of totally protected conservation zones is the only way to preserve this unique plant.
Gunung Gading National Park in Southwest Sarawak is such a conservation zone. Gazetted in 1983, the park covers an area of 4,106 hectares and forms a safe and secure habitat for the protection of the Rafflesia.
The Rafflesia is a rare flower with a short flowering period. Therefore a certain amount of luck is required if your visit to Sarawak is to coincide with a Rafflesia in full bloom. The park staff monitor the progress of the Rafflesia buds very closely, and usually know when a flower is about to bloom, so visitors can check with the park headquarters (Tel: 082-735714) or the National Parks Booking Office in Kuching (Tel: 082-248088).
A plank walk is situated near the park headquarters in an area where Rafflesia are often found. Park wardens also take visitors on guided walks to flowers that are blooming deeper in the forest. Visitors should take notice of the warden’s instructions and tread carefully, to avoid damaging any buds on the forest floor.
Rafflesia has no set flowering season, but blooms are more common at Gunung Gading during the wetter months (November to February). They are also more common on the lower slopes of the park’s mountain peaks.
Sourced from: www.sarawakforestry.com