Раффлезия Арнольди: Әлемдегі ең ірі гүл

Species of flowering plant

Rafflesia arnoldii, the corpse flower, or giant padma, is a species of flowering plant in the parasitic genus Rafflesia. It is noted for producing the largest individual flower on Earth. It has a strong and unpleasant odor of decaying flesh. It is native to the rainforests of Sumatra and Borneo. Although there are some plants with larger flowering organs like the titan arum (Amorphophallus titanum) and talipot palm (Corypha umbraculifera), those are technically clusters of many flowers. Rafflesia arnoldii is one of the three national flowers in Indonesia, the other two being the white jasmine (Jasminum sambac) and moon orchid (Phalaenopsis amabilis). It was officially recognized as a national "rare flower" in Presidential Decree No. 4 in 1993.

The first European to find Rafflesia was the ill fated French explorer Louis Auguste Deschamps. He was a member of a French scientific expedition to Asia and the Pacific, detained by the Dutch for three years on the Indonesian island of Java, where, in 1797, he collected a specimen, which was probably what is now known as R. patma. During the return voyage in 1798, his ship was taken by the British, with whom France was at war, and all his papers and notes were confiscated. Joseph Banks is said to have agitated for the return of the stolen documents, but apparently to no avail: they were lost, turned up for sale around 1860, went to the British Museum of Natural History, where they were promptly lost again. They did not see the light of day until 1954, when they were rediscovered at the Museum. To everyone's surprise, his notes and drawings indicate that he had found and studied the plants long before the British. It is thought quite possible the British purposely hid Deschamps' notes, to claim the 'glory' of 'discovery' for themselves. Arnold contracted a fever and died soon after the discovery, the preserved material being sent to Banks. Banks passed on the materials, In the kecamatan ('district') of Pandam Gadang, it is known as cendawan biriang in the Minangkabau language.

Although Rafflesia is a vascular plant, it lacks any observable leaves, stems or even roots, and does not have chlorophyll. It lives as a holoparasite on vines of the genus Tetrastigma. Similar to fungi, individuals grow as a mass of thread like strands of tissue completely embedded within and in intimate contact with surrounding host cells from which nutrients and water are obtained. It can only be seen outside the host plant when it is ready to reproduce; the only part of Rafflesia that is identifiable as distinctly plant like are the flowers, though even these are unusual since they attain massive proportions, have a reddish brown colouration, and stink of rotting flesh. The flower of Rafflesia arnoldii grows to a diameter of around , These flowers emerge from very large, cabbage like, maroon or dark brown buds typically about wide, but the largest (and the largest flower bud ever recorded) found at Mount Sago, Sumatra in May 1956 was in diameter. Indonesian researchers often refer to the bud as a 'knop' (knob). The plant is native to the rainforests of Malaysia and Indonesia.

Rafflesia arnoldii is found in both secondary and primary rainforests. The only host plant species of R. arnoldii is Tetrastigma leucostaphylum in West Sumatra. Tetrastigma are themselves parasites of a sort, using the strength and upright growth of other surrounding plants to reach the light. The host plants of the host plants – the trees that Tetrastigma uses to climb up to light, are relatively limited in number of species, although they are generally the closest tree to the vine. When it is young, at least at the locations studied in West Sumatra, areas of primary forest, the vine climbs on sapling trees and bushes of Laportea stimulans and Coffea canephora in the undergrowth, in the subcanopy a Campnosperma species is the most important, whereas the only large tree the vine grows in is also Laportea stimulans. Tetrastigma often can completely envelop its host at the subcanopy level, choking out the light to such degree that the forest floor below the canopy is completely dark–this is apparently preferred by Rafflesia arnoldii, as the most knops are found at the darkest locations in the forest. The most common plant associated with Rafflesia arnoldii is the smallish tree Coffea canephora (the well known robusta coffee), which is actually not native to the area, but was introduced from Africa. It covers most of the undergrowth, with a Importance Value Index (IVI) of over 100%, and is also the main component of the subcanopy with an IVI of 52.74%. The dominant tall tree in these areas is Toona sureni, which has a canopy IVI of 4.97%. When Rafflesia is ready to reproduce, a tiny bud forms outside the root or stem of its host and develops over a period of a year. The cabbage like head that develops eventually opens to reveal the flower. The stigmas or stamens are attached to a spiked disk inside the flower. A foul smell of rotting meat attracts flies and beetles. To pollinate successfully, the flies and/or beetles must visit both the male and female plants, in that order. The fruit produced are round berries filled with numerous minute seeds. The flies Drosophila colorata, Chrysomya megacephala and Sarcophaga haemorrhoidalis visit the late flowers. Black ants of the genus Euprenolepis may feed on the developing flower buds, perhaps killing them.

It has not been assessed for the IUCN Red List, but the conservation status of the Rafflesia arnoldii is currently of concern due to anthropogenic and biological factors. Anthropogenic factors contributing to the decline are primarily deforestation and harvesting; biological factors contributing to the decline include the plant's dioecious nature, limited population, and skewed sex ratio, with the majority of the flowers being male. However, ecotourism is thought to be a main threat to the species. At locations which are regularly visited by tourists the number of flower buds produced per year has decreased.