Rafflesia

Rafflesia is a genus of parasitic flowering plants in the family Rafflesiaceae. The species have enormous flowers, the buds rising from the ground or directly from the lower stems of their host plants; one species has the largest flowers in the world. The genus contains approximately 28 species (including four incompletely characterized species as recognized in 1997 by Willem Meijer in the latest monograph on the genus), all found in Southeast Asia, mainly in Indonesia, Malaysia, Thailand and the Philippines. For Western Europe, it was first discovered by French surgeon and naturalist Louis Deschamps in Java between 1791 and 1794, but his notes and illustrations, seized by the British in 1803, were not available to western science until 1861.[2] The first British person to see one was Joseph Arnold in 1818, in the Indonesia rainforest in Bengkulu, Sumatra, after a Malay servant working for him discovered a flower and pointed it out to him.[3] It was later named after Stamford Raffles, the leader of the expedition.

Rafflesia
Rafflesia arnoldii flower and buds, captured in Bengkulu, Indonesia
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Rosids
Order: Malpighiales
Family: Rafflesiaceae
Genus: Rafflesia
R.Br. ex Thomson bis[1]
Type species
Rafflesia arnoldii
Species

See Classification section

Arnold was quite excited when he saw his first flower, the following is from his account:[3]

"Here I rejoice to tell you I happened to meet with what I consider as the greatest prodigy of the vegetable world. I had ventured some way from the party, when one of the Malay servants came running to me ... To tell you the truth, had I been alone, and had there been no witnesses, I should, I think, have been fearful of mentioning the dimensions of this flower, so much does it exceed every flower I have seen or heard of."

Rafflesia is the official state flower of Indonesia, of Sabah state in Malaysia, and of Surat Thani Province in Thailand.

Description
Replica Rafflesia displayed in Philippine National Museum

The plant has no stems, leaves or roots. It is a holoparasite of vines in the genus Tetrastigma (a plant in the Vitaceae, the grape vine family), spreading its absorptive organ, the haustorium, inside the tissue of the vine.[4] The only part of the plant that can be seen outside the host vine is the five-petalled flower. In some species, such as Rafflesia arnoldii, the flower may be over 100 centimetres (40 in) in diameter, and weigh up to 10 kilograms (22 lb). A Rafflesia that flowered in West Sumatra in 2019 was measured to be almost 4 feet (120 cm) in diameter, the largest flower ever recorded – 4 inches (10 cm) wider than the flower reported as the largest in 2017.[5] Even one of the smallest species, R. baletei, has 12 cm (5 in) diameter flowers.

The flowers look and smell like rotting flesh. The foul odour attracts insects such as carrion flies, which transport pollen from male to female flowers. Most species have separate male and female flowers, but a few have hermaphroditic flowers. Little is known about seed dispersal. Tree shrews and other forest mammals eat the fruits.[6] The extremely tiny seeds have an extremely tiny elaiosomes, and are thus most likely dispersed by ants. The seeds are packed into berries, which contains hundreds of thousands of seeds.[4]

Because Amorphophallus has the world's largest unbranched inflorescence, it is sometimes mistakenly credited as having the world's largest flower. Both Rafflesia and Amorphophallus are flowering plants, but they are unrelated to each other. Rafflesia arnoldii has the largest single flower of any flowering plant, at least in terms of weight. Amorphophallus titanum has the largest unbranched inflorescence, while the talipot palm (Corypha umbraculifera) forms the largest branched inflorescence, containing thousands of flowers; the talipot is monocarpic, meaning the individual plants die after flowering.

Rafflesia are also remarkable for showing a large horizontal transfer of genes from their host plants. This is well known among bacteria, but not higher organisms. It also does not really occur in Rafflesia, but in the mitochondria found within the cells of Rafflesia, which were originally derived from bacteria, these appear to have exchanged genes with the mitochondria of the host tissue.[4][7]

Names

In Indonesian it is known as padma. R. arnoldii is known as padma paksasa (giant Rafflesia).[8] In Javanese it is called patma.[9] In Malay, the 'normal' R. hasseltii is vernacularly known as pakma, patma or ambai-ambai,[3][9][10] whereas the goliath R. arnoldii from Sumatra is called krubut or kerubut, 'great flower'.[3][10] The words padma, pakma or patma originate etymologically from the word पद्म (padma), Sanskrit for 'lotus'.[10]

A webpage for a class project by two American students, made in 2003, incorrectly stated that the local name translated to "corpse flower".[11] A month later this sentence was copied to Wikipedia,[12] but due to subsequent edits, by 2010 the sentence came to claim that the English name was "corpse flower",[13] and by 2020 this name has been used numerous times in news articles and the like.

The name "corpse flower" referred to the titan arum (Amorphophallus titanum) of the family Araceae.[4]

According to a CNN reporter, the flower has been called the "monster flower".[5]

Taxonomy

Robert Brown introduced the genus Rafflesia to the wider scientific world in a presentation before the Linnean Society of London in June 1820, but his scientific paper on the subject was only published in late 1821.[1]

In 1999 the British botanical historian David Mabberley pointed out that the genus Rafflesia was 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.[14] 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![15]

Evolution and phylogeny
Rafflesia keithii bloom, approximately 80 cm in diameter near Taman Nasional Rafflesia Bengkulu, Indonesia
Rafflesia kerrii flower near Langkat, Indonesia
Three Rafflesia pricei growing in close proximity near Mount Kinabalu, Borneo

Comparison of mitochondrial DNA (mtDNA) sequences of Rafflesia with other angiosperm mtDNA indicated this parasite evolved from photosynthetic plants of the order Malpighiales.[16] Another 2004 study confirmed this result using both mtDNA and nuclear DNA sequences, and showed the three other groups traditionally classified in Rafflesiaceae were unrelated.[17] A 2007 study more specifically found Rafflesia and its relatives to be embedded within the family Euphorbiaceae as traditionally circumscribed, which was surprising, as members of that family typically have very small flowers. According to their analysis, the rate of flower size evolution was more or less constant throughout the family except at the origin of Rafflesiaceae, where the flowers rapidly evolved to become much larger before reverting to the slower rate of change.[18]

To maintain monophyletic families, in 2016 the APG IV system separated the family Peraceae from the Euphorbiaceae.[19] A summary cladogram is shown below,[18] with family placements in the APG IV system.[19]

Euphorbiaceae sensu lato
 

Peraceae (3 genera in the study)

 
 
Rafflesiaceae
 

Sapria

 
 
 

Rhizanthes

 
 

Rafflesia

 
 
 
 

Euphorbiaceae sensu stricto (18 genera in the study)

 
 
 

A 2020 molecular phylogenetic study of 18 species of Rafflesia found that they fell into four clear-cut geographically defined groups:[20]

Rafflesia
Philippines group
 

Rafflesia speciosa

 
 
 

Rafflesia manillana

 
 
 

Rafflesia lobata

 
 

Rafflesia sp.

 
 
 
 
 
Peninsular Malaysia group
 

Rafflesia kerrii

 
 
 

Rafflesia cantleyi

 
 

Rafflesia azlanii

 
 
 
 
Borneo group
 

Rafflesia tuan-mudae

 
 
 

Rafflesia tengku-adlinii

 
 
 

Rafflesia keithii

 
 

Rafflesia pricei

 
 
 
 
Sumatra + Java group
 
 

Rafflesia patma

 
 

Rafflesia rochussenii

 
 
 
 

Rafflesia zollingeriana

 
 
 

Rafflesia gadutensis

 
 
 

Rafflesia hasseltii

 
 
 

Rafflesia micropylora

 
 

Rafflesia arnoldii

 
 
 
 
 
 
 
 
 

However, the clear monophyly of the four geographical clades does not correspond to any clear difference in appearance. There is no consistency within the clades in the size of flowers, or the presence or absence of white warts; species in different clades resemble one another more than they do some other species within the same clade. Homoplasy – repeatedly gaining or losing traits – seems to be the rule within Rafflesia.[20]

Accepted species

As of October 2020, Plants of the World Online accepted the following species:[21]

Other names
  • Rafflesia patma – Java; considered a synonym of R. horsfieldii by Plants of the World Online,[21] apparently based on the confused writings of a British historian of botany,[14] although R. horsfieldii, for which no specimens were ever collected, only a drawing made which was lost centuries ago, is not considered a valid taxon by Rafflesia experts.[23]
  • Rafflesia titan - A synonym of R. arnoldii; it was in fact validily published earlier, being rushed to publication in Singapore in 1820 by a British botanist who feared that the French, who had actually discovered a species before the British, might deny the glory of the species description to servants of the British Empire.[2] In order to retain the honour of naming the species to the famous British scientist Robert Brown, the historian of botany mentioned above chose to pretend a 1821 pre-print Brown sent to a colleague was a valid 'effective publication',[14] which has been accepted by the relevant British institutions.[21][24]

Loss of the chloroplast genome

Research published in 2014 revealed that one Philippine Rafflesia species from the island of Luzon, R. lagascae (a synonym of R. manillana), may have lost the genome of its chloroplast and it is speculated that the loss happened due to the parasitic lifestyle of the plant.[7]

Distribution

In Thailand Rafflesia can be observed in Khao Sok National Park where the flowers are numbered and monitored by the park rangers.[25]

Bornean species

Species native to Borneo include Rafflesia arnoldii, R. cantleyi, R. hasseltii, R. keithii, R. kerrii, R. pricei, R. tengku-adlinii and R. tuan-mudae. R. arnoldii boasts the world's largest single bloom.[26] R. keithii begins blooming at night and start to decompose only two to three days later. The time from bud emergence to flowering is six to nine months. R. keithii is found along the eastern slopes of Mount Kinabalu in the Lohan Valley of Sabah.

Mindanao (Philippines) species

The Mindanao species is known as Rafflesia schadenbergiana, after the naturalist Alexander Schadenberg, who first discovered the species at the foothills of Mount Apo in 1882. With a flower of nearly a meter, it is close to the size of a 7 year old child when seated. On Mindanao, the species has been seen in Davao del Sur, South Cotabato and Mount Kitanglad in Bukidnon.[27] R. mira and R. magnifica are two names for a single species. Both were discovered at Mount Candalaga in Maragusan, Compostela Valley. The two forms differ in size measurements in which the scientific description of R. magnifica came from measurements of flowers in full bloom while that of R. mira was from photographs of nearly dead samples. The medium-sized R. mira flowers measure about half a meter in diameter and they have round or elliptic perigone wart.[28] The third species on Mindanao is the R. mixta which has only been found so far in the town of Mainit, Surigao del Norte. It shows a combination of three features of Philippine Rafflesia, namely: the shape and size of the conical process in R. schadenbergiana, the floral size and sparsely distributed perigone warts of R. speciosa, and the overall resemblance, floral size, faint scent, diaphragm and ramenta morphology of R. mira.[29] A fourth species is Rafflesia verrucosa which is found only in Mount Kampalili in Davao Oriental Province.[30]

Ecology

Species of Rafflesia are all thought to be holoparasites of lianas of the genus Tetrastigma, vines which belong to the Vitaceae, the family of the grape vines. They are thus, in a way, hyperparasites, because Tetrastigma are themselves, in a way, structural parasites of the trees they use to climb up to the light. Rafflesia appear to be species-specific, with each Rafflesia species naturally only growing on one to three species of Tetrastigma. Of the 57 known species of Tetrastigma, only ten are known to be host plants. Of the 30 odd species of Rafflesia, the host plants are only known from about half of the species. Strangely, a certain species of Tetrastigma is very popular among Rafflesia, T. tuberculatum is a host plant for at least 15 species, only two Philippine species are not known to infect it. T. papillosum and T. diepenhorstii both host at least two species. The flowers may bud from different locations, R. cantleyi flowers from the vine some two meters from the ground, [31] whereas R. zollingeriana always buds out of the roots and appears out of the ground.[32]

The gender ratio may be skewed. In R. lobata there are approximately nine male flowers for every female flower.[33] Rarely are there flowers of both sexes at one location to ensure pollination and thus sexual reproduction. This may not matter: female flowers usually form fruit anyway and may thus be agamospermous.[31] Flowering is relatively constant, and sites may continue to flower for decades.[34][35]

In Rafflesia arnoldii the flowers are visited by the flies Drosophila colorata, Chrysomya megacephala and Sarcophaga haemorrhoidalis. Black ants of the genus Euprenolepis may feed on the developing flower buds, perhaps killing them.[36] Mammals which are known to eat the flowers are the Javan treeshrew Tupaia javanica and the porcupine Hystrix javanica. Mammals which have been recorded destroying the buds or flowers, often simply by stepping on and crushing them, are: pigs (Sus scrofa), wild cats (Felis bengalensis), rusa (Cervus timorensis), muntjak (Muntiacus muntjak) and banteng (Bos javanicus).[31]

Uses

In Thailand the buds and flowers of R. kerrii are considered a delicacy. They are also harvested for herbalism, a concoction is believed to act as a sexual stimulant and to help for fever or backache.[37] In the Philippines the plants are also used in folk herbalism, but the flowers are also fed to swine as fodder.[35] On Java the buds of R. zollingeriana are harvested and dried for use in jamu, the ancient traditional herbalism of the island. It is unknown for what the buds are supposed to be good for;[34] jamu concoctions are often complex mixtures and often are supposed to help with sexual prowess.

These plants also have some economic use in attracting ecotourists.[38]

Research in Malaysia and Indonesia has made it possible to propagate the species for use in horticulture, with the famous Bogor Botanical Garden growing the first plants in the 1850s using grafts of infected vines. The Malaysian biologist Jamili Nais was the first to propagate the plants using the seeds around the year 2000.[31]

See also

References
  1. "Rafflesia". International Plant Names Index. The Royal Botanic Gardens, Kew, Harvard University Herbaria & Libraries and Australian National Botanic Gardens. Retrieved 29 October 2020.
  2. Willem, Meijer (1997). "Rafflesiaceae". Flora Malesiana. 13. Leiden: Hortus Botanicus Leiden, under auspices of Foundation Flora Malesiana. p. 1-42. ISBN 90-71236-33-1.
  3. Keng, Hsuan (1978). Orders and Families of Malayan Seed Plants (revised ed.). Singapore: Singapore University Press (original published by University of Malaya Press 1969). p. 106.
  4. Shaw, Jonathan (March–April 2017). "Colossal Blossom: Pursuing the peculiar genetics of a parasitic plant". Harvard Magazine. Retrieved 27 June 2017.
  5. Scottie Andrew. "Scientists just found one of the world's largest flowers blooming in an Indonesian jungle". CNN. Retrieved 5 January 2020.
  6. "Rafflesia arnoldii (corpse flower)". Plants & Fungi (blog). Kew Botanical Gardens. 2011. Archived from the original on 2014-02-20. Retrieved 29 October 2020. note: unverified errata info possibly from Mabberley (1985)
  7. Molina, Jeanmaire; Hazzouri, Khaled M.; Nickrent, Daniel; Geisler, Matthew; Meyer, Rachel S.; et al. (2014). "Possible Loss of the Chloroplast Genome in the Parasitic Flowering Plant Rafflesia lagascae (Rafflesiaceae)". Molecular Biology and Evolution. 31 (4): 793–803. doi:10.1093/molbev/msu051. PMC 3969568. PMID 24458431.
  8. Atmosumarto, Sutanto (2004). A learner's comprehensive dictionary of Indonesian. Atma Stanton. p. 445. ISBN 9780954682804.
  9. Burkill, Isaac Henry (April 1930). "An Index to the Malay Vernacular Names with comments". The Gardens' Bulletin; Straits Settlements. 3 (6 (part 2)): 300. Retrieved 27 October 2020.
  10. Sir Richard James Wilkinson (primarily based on the works of). "Searching native orthography for "patma", "pakma"". SEAlang Library Malay. SEAlang. Retrieved 28 October 2020.
  11. Nicholson, Chris; Given, Beth (1 April 2003). "The Genus Rafflesia". Biology 226 class project on the conservation of global biodiversity. Earlham College. Retrieved 28 October 2020.
  12. https://en.wikipedia.org/w/index.php?title=Rafflesia&oldid=901731 this article, 7 May 2003
  13. https://en.wikipedia.org/w/index.php?title=Rafflesia&oldid=428346181
  14. Mabberley, David John (1999). "Robert Brown on Rafflesia" (PDF). Blumea. 44 (2): 343–350. ISSN 2212-1676. Retrieved 28 October 2020.
  15. "Thomson bis". International Plant Names Index. The Royal Botanic Gardens, Kew, Harvard University Herbaria & Libraries and Australian National Botanic Gardens. Retrieved 29 October 2020.
  16. Barkman, T. J.; S.-H. Lim; K. Mat Salleh; J. Nais (January 20, 2004). "Mitochondrial DNA sequences reveal the photosynthetic relatives of Rafflesia, the world's largest flower". PNAS. 101 (3): 787–792. doi:10.1073/pnas.0305562101. PMC 321759. PMID 14715901.
  17. Nickrent, D. L.; A. Blarer; Y.-L. Qiu; R. Vidal-Russell; F. E. Anderson (October 20, 2004). "Phylogenetic inference in Rafflesiales: the influence of rate heterogeneity and horizontal gene transfer". BMC Evolutionary Biology. 4: 40. doi:10.1186/1471-2148-4-40. PMC 528834. PMID 15496229.
  18. Davis, Charles C.; Latvis, Maribeth; Nickrent, Daniel L.; Wurdack, Kenneth J. & Baum, David A. (2007-03-30), "Floral Gigantism in Rafflesiaceae", Science, 315 (5820): 1812, Bibcode:2007Sci...315.1812D, doi:10.1126/science.1135260, PMID 17218493, S2CID 27620205
  19. Angiosperm Phylogeny Group (2016), "An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG IV", Botanical Journal of the Linnean Society, 181 (1): 1–20, doi:10.1111/boj.12385
  20. Bendiksby, Mika; Schumacher, Trond; Gussarova, Galina; Nais, Jamili; Mat-Salleh, Kamarudin; Sofiyanti, Nery; Madulid, Domingo; Smith, Stephen A. & Barkman, Todd (2010-11-01). "Elucidating the evolutionary history of the Southeast Asian, holoparasitic, giant-flowered Rafflesiaceae: Pliocene vicariance, morphological convergence and character displacement". Molecular Phylogenetics and Evolution. 57 (2): 620–633. doi:10.1016/j.ympev.2010.08.005. PMID 20723606.
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  22. "Rafflesia leonardi Barcelona & Pelser". Parasitic Plant Connection, Southern Illinois University. Retrieved 28 June 2017.
  23. Meijer, W.; Veldkamp, J. F. (1988). "A revision of Rhizanthes (Rafflesiaceae)" (PDF). Blumea. 33 (2): 329–342. ISSN 2212-1676. Retrieved 28 October 2020.
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  25. "Where to see Rafflesia in Thailand – the biggest flower in the world". 203 Challenges.
  26. "Rafflesia Facts - Rafflesia, The World's Largest Bloom". RafflesiaFlower.com. Retrieved 14 September 2016.
  27. Barcelona, J.F., P.B. Pelser, A.M. Tagtag, R.G. Dahonog & A.P. Lilangan. 2008. The rediscovery of Rafflesia schadenbergiana Göpp. ex Hieron. (Rafflesiaceae). Flora Malesiana Bulletin 14: 162-165.
  28. Madulid, D.A.; Tandang, D.N. & Agoo, E.M.G. (2008). "Rafflesia magnifica". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 22 November 2013.
  29. M.E. Manting, R.B. Arbolonio, R.B. Caballero & P.B. Pelser. 2014. Rafflesia mixta (Rafflesiaceae), a new species from Surigao del Norte, Mindanao, Philippines
  30. Balete, D.S., P.B. Pelser, D.L. Nickrent & J.F. Barcelona. 2010. Rafflesia verrucosa (Rafflesiaceae), a new species of small-flowered Rafflesia from eastern Mindanao, Philippines. Phytotaxa 10: 49-57.
  31. Susatya, Agus (October 2011). Rafflesia Pesona Bunga Terbesar di Dunia (PDF) (in Indonesian). Jakarta: Direktorat Kawasan Konservasi dan Bina Hutan Lindung. p. 67-69, 83-84, 86. ISBN 978-602-19319-0-5.
  32. Maezulpah, N.; Briliawan, B. D.; Fairuz, R.; Iman, D. T.; Pratama, M.; Ahsania, D. A.; Nurhayati; Saidah, I.; Nurhaeni, W.; Hidayati, S. N.; Khoirunnisa, E.; Tyas, A.; Hikmat, Agus (2019). "Population structure and conservation strategy of Rafflesia zollingeriana Koord. in Bandealit Resort, Meru Betiri National Park". IOP Conference Series: Earth and Environmental Science. 394 (1): 012008. Bibcode:2019E&ES..394a2008M. doi:10.1088/1755-1315/394/1/012008. Retrieved 7 November 2020.
  33. Lestari, Dewi; Hikmat, Agus; Zuhud, Ervizal Amir Muhammad (April 2014). "Conservation Strategy of Rafflesia zollingeriana Koord in Meru Betiri National Park, East Java". Jurnal Manajemen Hutan Tropika (Journal of Tropical Forest Management). 20 (1): 9. doi:10.7226/jtfm.20.1.9. ISSN 2087-0469. Retrieved 8 November 2020.
  34. Damayanti, Ellyn K.; Zuhud, Ervizal A. M.; Hikmat, Agus; Lestari, Dewi; Syarief, N. R. (9 October 2014). "Conservation of Rafflesia zollingeriana: Integrating conservation policy with local livelihood". In J. A. Parrotta; C. F. Moser; A. J. Scherzer; N. E. Koerth; D. R. Lederle (eds.). International Forestry Review - Abstracts for XXIV IUFRO World Congress. XXIV IUFRO World Congress "Sustaining Forests, Sustaining People: The Role of Research", 5-11 October 2014, Salt Lake City, USA. 16. pp. 49–75. doi:10.13140/2.1.2631.6801. Retrieved 4 November 2020.
  35. Barcelona, J.F.; P.B Pelser; D.S. Balete; L.L. Co (October 2009). "Taxonomy, ecology, and conservation status of Philippine Rafflesia (Rafflesiaceae)". Blumea. 54: 77–94. doi:10.3767/000651909X474122.
  36. Pranata, Syafroni; Sulistijorini; Chikmawati, Tatik (September 2019). "Ecology of Rafflesia arnoldii (Rafflesiaceae) in Pandam Gadang, West Sumatra". Journal of Tropical Life Science. 9 (3): 243–251. doi:10.11594/jtls.09.03.05. Retrieved 30 October 2020.
  37. Jamili Nais (2001). Rafflesia of the world. Kota Kinabalu: Sabah Parks. ISBN 978-983-812-042-5. OCLC 50043098.
  38. Barkman, Todd J. (2000). "Rafflesia". Barkman's homepage. Western Michigan University. Retrieved 9 November 2020.

Further reading
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