Rafflesia arnoldii

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.[9] Joseph Banks is said to have agitated for the return of the stolen documents, but apparently to no avail:[10] 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.[9]

In 1818[2] the British surgeon Joseph Arnold collected a specimen of another Rafflesia species found by a Malay servant in a part of Sumatra, then a British colony called British Bencoolen (now Bengkulu), during an expedition run by the recently appointed Lieutenant-Governor of Bencoolen, Stamford Raffles.[11] Arnold contracted a fever and died soon after the discovery, the preserved material being sent to Banks. Banks passed on the materials,[2] and the honour to study them was given to Robert Brown. The British Museum's resident botanical artist Franz Bauer was commissioned to make illustrations of the new plants. Brown eventually gave a speech before the June 1820 meeting of the Linnean Society of London, where he first introduced the genus and its until then two species.[10] Brown gave the generic name Rafflesia in honour of Raffles.[2] Bauer completed his pictures some time in mid-1821, but the actual article on the subject continued to languish.[10]

William Jack, Arnold's successor in the Sumatran Bencoolen colony, recollected the plant and was the first to officially describe the new species under the name R. titan in 1820. It is thought quite likely that Jack rushed the name to publication because he feared that the French might publish what they knew of the species, and thus rob the British of potential 'glory'.[9] Apparently aware of Jack's work, Brown finally had the article published in the Transactions of the Linnean Society a year later, formally introducing the name R. arnoldii[10] (he ignores Jack's work in his article).

Specimen of Rafflesia arnoldii at the Kyoto Botanical Garden

Because Jack's name has priority, R. arnoldii should technically be a synonym of R. titan, but at least in Britain, it was common at the time to recognize the names introduced by well-regarded scientists such as Brown, over what should taxonomically be the correct name. This was pointed out by the Dutch Rafflesia expert Willem Meijer in his monographic addition to the book series Flora Malesiana in 1997. Instead of sinking R. arnoldii into synonymy, however, he declared that the name R. titan was "incompletely known": the plant material used by Jack to describe the plant has been lost.[9]

In 1999, the British botanical historian David Mabberley, in response to Meijer's findings, attempted to rescue Brown's names from synonymy. This is known as 'conservation' in taxonomy, and normally this requires making a formal proposal to the committee of the International Code of Botanical Nomenclature (ICBN). Mabberley thought he found a loophole around such a formal review by noting that while Brown was notoriously slow to get his papers published, he often had a handful of pre-print pages privately printed to exchange with other botanists: one of these pre-prints had been recently bought by the Hortus Botanicus Leiden, and it was dated April 1821. Mabberley thus proposed that this document be considered the official effective publication, stating this would invalidate Jack's earlier name. For some reason Mabberley uses 1821, a few months after Brown's pre-print, as the date of Jack's publication, instead of the 1820 publication date in Singapore.[10] Confusingly, the record in the International Plant Names Index (IPNI) still has yet another date, "1823?", as it was in the Index Kewensis before Meijer's 1997 work.[1][9] Mabberley's proposals regarding Brown's name were accepted by institutions, such as the Index Kewensis.[1]

Mabberley also pointed out that the genus Rafflesia was thus first validated by an anonymous report on the meeting published in the Annals of Philosophy in September 1820 (the name was technically an unpublished nomen nudum until this publication). Mabberley claimed the author was Samuel Frederick Gray.[10] However, as that is nowhere stated in the Annals, per Article 46.8 of the code of ICBN, Mabberley was wrong to formally ascribe the validation to Gray. The validation of the name was thus attributed to one Thomas Thomson, the editor of the Annals in 1820, by the IPNI. Mabberley admitted his error in 2017.[1] This Thomson was not the botanist Thomas Thomson, who was three years old in 1820, but his identically named father, a chemist, and Rafflesia is thus the only botanical taxon this man ever published.[1]

It is called kerubut in Sumatra.[12] In the kecamatan ('district') of Pandam Gadang, it is known as cendawan biriang in the Minangkabau language.[13]

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.[14] 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.[15]

The flower of Rafflesia arnoldii grows to a diameter of around one meter (3.3 feet),[2] weighing up to 11 kilograms (24 lb).[16] These flowers emerge from very large, cabbage-like, maroon or dark brown buds typically about 30 cm (12 in) wide, but the largest (and the largest flower bud ever recorded) found at Mount Sago, Sumatra in May 1956 was 43 cm (17 in) in diameter.[17] Indonesian researchers often refer to the bud as a 'knop' (knob).[13]

Called a "monster flower", Rafflesia arnoldii produces the largest single bloom and can grow up to three feet (one meter) in diameter and weigh up to 15 pounds (6.8 kg).[18] The plant is native to the rainforests of Malaysia and Indonesia.[19]

It has not been assessed for the IUCN Red List. 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.[2]

• Largest organisms

• Meijer, Willem (July 1985). "Saving the World's Largest Flower". National Geographic. Vol. 168, no. 1. pp. 136–140. ISSN 0027-9358.

Wikispecies has information related to Rafflesia arnoldii.

• Media related to Rafflesia arnoldii at Wikimedia Commons
• Rafflesia arnoldii at Parasitic Plant Connection