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Rafflesia – Queen of Parasites and the Biggest Flower on Earth
Rafflesia is the world’s largest flower which belongs to the genus of parasitic flowering plants. Rafflesia is the official state flower of Indonesia, the Sabah state in Malaysia, and also for the SuratThaniProvince, Thailand.This flower was discovered in the Indonesian rain forest by an Indonesian guide working for Dr. Joseph Arnold in 1818. it was named after Sir Thomas Stamford Raffles, the leader of the expedition. These rare flowers are found in southeastern Asia in the forests of the Malaysian states of Sabah and Sarawak, in the rainforests of Indonesia, Borneo and the Philippines. It contains approximately 29 species out of which four are not completely recognised species.
It is a parasitic plant, with no visible leaves, roots, or stem. It attaches itself to a host plant to obtain water and nutrients. The plant produces no leaves, stems or roots and does not contain chlorophyll and are therefore incapable of photosynthesis. It is an endoparasite of vines spreading its roots inside the tissue of the vine to obtain water and nutrients. It is totally dependant upon a vine called Tetrastigma, which is related to the grapevine. The only part of the plant that can be seen outside the host vine is the five-petaled flower.When in bloom; the Rafflesia emits a foul odour, similar to that of rotting meat which gives this flower its local names which mean corpse flower or meat flower. This odour attracts insects such as flies and carrion beetles, which transport pollen from male to female flowers. The Rafflesiaarnoldii, may be over 100 centimetres in diameter, and weigh up to 10 kilograms (22 lb).
The Rafflesia can only be seen when it is ready to reproduce. At this stage a tiny bud forms on the stem of the vine which develops for a period of about a year (9 to 12 months) resembling a cabbage. This cabbage-like bud will open up to reveal the massive 5-petaled flower. The flower has a spiked disk to which stamens and pistils are attached, which develop into a fruit with seeds. The flowers sit on the forest floor and are unisexual either male or female. The center of the flowers contains numerous spikes and also holds several gallons of nectar. The fruit produced by Rafflesia is round and about 15cm in diameter. It is filled with smooth flesh and thousands of tiny hard coated seeds. The fleshy fruit attracts squirrels and tree shrews which are the main distributors of the seeds.
Pollination in Rafflesia is a rare due to several factors. the flowers are unisex and same sex plants are found near to each other. For pollination to be successful, the insect pollinators have to visit both male and female plants. Both sex flowers are not only far from each other, but they also have to open and be mature at the same time. While male and female individuals could be closely spaced, flower bud mortality is 80-90 % per site thereby reducing the chance of co-flowering of two individuals. Apart from this, to make things complicated the flowers last less than a week (5 to 7 days), leaving a narrow time frame window of opportunity for pollination.
There have been several challenges in studying the rafflesia for 190 years now since its discovery. The reasons behind this are:
- Rafflesia grows entirely embedded within the body of the host plant that they parasitize, and are only visible when they erupt from within the host body as a flower bud. Although other means of studying Rafflesia, like anatomical sectioning, could be performed, this method would likely result in death of both the host and parasite.
- Rafflesia is rare in occurrence and can only be found in remote lowland forests of Southeast Asia. Much of its habitat in these regions have been converted to farm land or timber concessions and in some parts of its range, the buds are harvested and sold for their intended medicinal qualities.
- Rafflesia become visible as flowers, and only survives a few days before decomposing.
The Largest Flower in the World
All of these factors make it difficult to even find Rafflesiasites. 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. These buds are seen as a sign of fertility, and are given to help mothers recover after birth. The over collection of these buds in the aim of helping with conservation efforts has only reduced the number of Rafflesia in the wild drastically. All these factors lead to decreasing numbers of Rafflesia.
Many species of Rafflesia are vulnerable to deforestation and development and becomes more threatened. 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.