Rafflesia
is a genus of endophytic, holoparasitic plants, well-known for producing the
largest bloom in the world. There are approximately 55 Rafflesia species distributed globally, with 30 species distributed
across South-east Asia region, from Thailand through Malaysia, island of
Borneo, Sumatra, Java and Philippines. Out of the 30 species, 11 species
recorded found in Malaysia. The species natives to peninsular Malaysia are Rafflesia hasseltii, Rafflesia cantleyi, Rafflesia kerii and Rafflesia
azlanii. Apart from that, Rafflesia
su-meiae found to be the largest flower in peninsular Malaysia. There are
also another listed six species found in Sabah and Sarawak. They are Rafflesia arnorldii (Western Sarawak), Rafflesia hasseltii (Samunsam, Sarawak),
Refflesia keithii (Sabah, possibly
Sarawak), Rafflesia pricei (Sabah
& Sarawak), Rafflesia tengku-adlinii
(Sabah) and Rafflesia tuan- mudae
(Sarawak).
Rafflesia
has many vernacular names given by the locals. This include bunga pakma, bunga
pecah belah, bunga kobis, bunga akar, kerubut, kekuanga, yak-yak, wusak,
tumbuakar, bunga matahari, devil’s betel box, sun mushroom, dai huang hua,
monarch flower, sun toadstool, corpse flower, and stinking corpse lily. The
members of Rafflesiaceae family are usually dioecious and unisexual. Dioecious
refers to an individual plant that produces either a female or male flower.
However, 2 species from the Philippines which are Rafflesia baletei and Rafflesia
verrucosa are monoaecious, which mean they produced bisexual flowers in one
individual plant.
Figure 1: Rafflesia keithii blooms on the first
day and last for 3 to 4 days in Poring, Sabah.
The
generic name Rafflesia was given to honour
Sir Raffles who is the founder of Rafflesia arnoldii
(and also the founder of new Singapore). The story begins in 1818, where a
British botanist named Dr. Joseph Arnold along with Sir Thomas Stamford Bingley
Raffles had collected a gigantic flower found by an unnamed Malay servant during
their tour in Bengkulu, Sumatra, Borneo. The name Rafflesia arnoldii is to commemorate the two naturalist and was
described for the first time by Robert Brown in 1821. Despite that, the first Rafflesia specimen was actually
collected by a French naturalist-surgeon called Louis Auguste Deschamps in
1797. However in 1798, all his works were confiscated when the French
expedition ship was captured by the British while returning back to France. Not
until 1954, all his papers and notes were rediscovered in the Natural History
Museum, London. Since 1821, various Rafflesia
species have been named and described by botanist and scientist. Yet, not all
of them are recognized and taxonomically resolved. One unidentified species
found in unprotected Gumanti Forest, Solok, and another one found in
unprotected forest of Pesisir Selatan, Indonesia. To date, much of the flower’s
biology remains unknown.
Not
all Rafflesia are gigantic but they
are definitely the largest blooms in the world. Rafflesia arnorldii recorded as the largest flower species in the
world with diameter up to 150 cm and weight about 11 kg. However, the largest
bloom of peninsular Malaysia is the 95 cm R.
su-meiae. Rafflesia baletei,
endemic to Philippines recorded as the smallest flower with approximately 15 cm
in diameter. Fascinating facts about the flower is, it is rootless and does not
have any leaves. They lack of chlorophyll which is an organelle needed by all
green plants (autotroph) to process their own food. Therefore, Rafflesia lives as a parasite to a
specific host called lianas, (belong
to Tetrastigma sp.) for protection, nutrition
and survival.
Figure 2: The bud of Rafflesia
keithii needs 6-9 months to full blooms.
Animals
such as squirrels, tree shrews, ants, boars and elephant are the dispersal
agents of the seeds of Rafflesia. The
seeds germinate on the specific host of lianas
and penetrate the vines, growing into red bud which looks like a cabbage.
The elapse of time for Rafflesia to
blooms varies between species: R.
arnoldii (67%), R. keithii (75%),
R. kerrii (54%), R. pricei (90%) and R.
tuan-mudae (80%). The caused might be related with the condition of the
host vines, high in humidity and the condition of the soil itself which exposed
the bud to predation by rodents, wasp larvae and termites. However, R. cantleyi, R. kerrii, R. keithii, R. pricei and R. tengku-adlinii blooms throughout the year.
The
pollinators of Rafflesia flowers are
bluebottles and carrion flies. They are basically attracted by the sight of the
blooms and its bad odor which similar to rotting flesh. Pollination in Rafflesia from male anther to female stigma must be very quickly as
the blooms do not last very long. Rafflesia
arnoldii, for instance blooms perfectly after 7-9 months and can last for 7
days. Rafflesia keithii only blooms
after 6-9 months at night and start to deteriorate after three days while R. pricei start to deteriorate after 2
or 3 days and completely turned into black glop by 15 days. Similar to other
flowers, after pollination the fruit is formed. Successful pollination will result
in a 15 cm fruits that set thousands of seeds. Some of the main factors that
contribute to unsuccessful pollination are limited number of individuals, bud
die before flourish, male flower and female flower does not blooms
simultaneously, unbalanced ratio of male flower and female flower and short
anthesis period.
Because
of the issues stated in previous paragraph, Rafflesia
is said to be a rare, vulnerable life-form. Not only because of its life-span
is very short, its blooming factor is totally depends on the presence of host
and the occurrence of the pollination. Pollination for Rafflesia is tough as the male and female flower grow on separate
plant. To ensure pollination will occur, the male and female plant must blooms
at the same time and in close proximity to enables flies pass between them.
Figure 3: Emergence bud of Rafflesia tuan-mudae in Gading National Park, Sarawak.
As
a vulnerable plant that only grows on certain species of vine called liana, the
Rafflesia are exposed to threats such
as ecotourism, commercial logging activities, slash and burns agriculture
threats and constructions of highways and hydroelectric dam. Regardless its
habitat is being disturbed, locals sought after this flower for its medicinal
purposes. We do have conservation in situ programme to protect the Rafflesia but conserving its habitat
alone is just not enough. IUCN Categories and Criteria showed that Rafflesia are highly endangered species.
One fact that everyone should worry of is that no one has ever cultivate the Rafflesia species.
