Nepenthes muluensis
Encyclopedia
Nepenthes muluensis or the Mulu Pitcher-Plant, is a tropical pitcher plant
endemic to Borneo
. It grows in highland habitats at elevations of 1700 to 2400 m above sea level.
on March 18, 1964, on Mardi between the third and fourth camps on the western ridge of Mount Mulu
. The holotype
, M.Hotta 14791d, is deposited at the Botany Department of Kyoto University
(KYO). Hotta described the species in 1966, naming it after Mount Mulu
, to which it was thought to be endemic. The description did not cover the lower pitchers of this species, which were unknown at the time. Nepenthes muluensis was the first Nepenthes species to be described in 26 years (after N. densiflora
in 1940) and the first since the end of World War II
. At this time the genus was experiencing a revival in global interest, thanks largely to the work of Shigeo Kurata
.
Nepenthes muluensis has been misidentified at least once in the literature; Bertram Evelyn Smythies identified specimens of N. muluensis as belonging to N. gracillima
, a species endemic to Peninsular Malaysia
. This misidentification was published in 1965 in the proceedings of the UNESCO Humid Tropics Symposium, which was held in Kuching
two years earlier.
s are cylindrical in cross section and up to 8 cm long.
The leaves of this species are coriaceous and sessile. The lamina is lanceolate in shape and up to 8 cm long by 1.5 cm wide. It usually has an acute apex and is gradually attenuate towards the base, extending into an amplexicaul sheath. Up to 4 longitudinal veins are present on either side of the midrib. Pinnate veins are numerous but indistinct. Tendril
s are up to 8 cm long.
Rosette and lower pitchers are up to 7 cm high and 3 cm wide. They are ovate in the lower third, becoming cylindrical or conical above. The peristome
is approximately cylindrical and up to 5 mm wide. Its inner margin is lined with small but distinct teeth. The pitcher mouth is round to ovate and has an oblique insertion. The lid or operculum
is ovate and generally obtuse. It bears a number of filiform appendages (≤5 mm long) on its upper surface.
Upper pitchers are cylindrical and often bulbous in the lowermost part. Like their lower counterparts, they are relatively small, reaching only 10 cm in height and 2 cm in width. They have a pair of ribs in place of wings. The pitcher mouth is round and bears a cylindrical peristome up to 3 mm wide. The lid is orbicular and lacks appendages. An unbranched spur
in inserted near the base of the lid.
Nepenthes muluensis has a racemose
inflorescence
. It is very compact: the peduncle
is only up to 3 cm long, while the attenuate rachis
reaches 10 cm in length. Pedicels
are up to 5 mm long and lack bract
s. Sepal
s are ovate and up to 2 mm long. A study of 120 pollen
samples taken from two herbarium specimens (J.H.Adam 2401 and J.H.Adam 2405) found the mean pollen diameter to be 32.0 μm
(SE
= 0.4; CV
= 8.7%).
The species completely lacks an indumentum
, with all parts of the plant being glabrous.
The type population of N. muluensis from Mount Mulu
has a distinctive pitcher colouration. Lower pitchers are generally dark purple with sparse yellow speckles. The upper pitchers of this form are usually purple with numerous yellowish-white speckles. They often have a white peristome and lid. Plants from Mount Murud
produce darker-coloured pitchers.
. However, since its description it has also been recorded from several other mountains, including Mount Murud
and Bukit Batu Lawi
. Nepenthes muluensis has not been recorded from the nearby summits of Mount Api
and Mount Benarat, although these are limestone
peaks and mostly lie outside the known altitudinal distribution of the species, which is 1700 to 2400 m above sea level.
Nepenthes muluensis grows in nutrient-deficient soils of the upper montane zone. It typically occurs in open areas of mossy forest amongst ridge-top vegetation. On Mount Mulu, the species seems to be restricted to the western ridge and occurs from an elevation of around 1900 m to the summit at 2376 m. The summit vegetation is greatly stunted, rarely exceeding a metre in height. It is dominated by rhododendron
s (particularly Rhododendron ericoides), as well as species of the genera Diplycosia and Vaccinium
. Nepenthes muluensis is most abundant in summit heath forest
, where it forms dense stands with hundreds of white-speckled pitchers suspended over the sympatric shrubs.
On Mount Murud, N. muluensis grows in shady mossy forest. This population produces darker pitchers than the one from Mount Mulu, possibly due to greater exposure to ultraviolet
light at higher altitudes. Two true toad
species from Mount Murud, Pelophryne linanitensis
and Pelophryne murudensis
, are sympatric with N. muluensis and may breed in its pitchers.
The conservation status
of N. muluensis is listed as Vulnerable
on the 2006 IUCN Red List of Threatened Species
based on an assessment carried out in 2000. This differs from the assessment made by the World Conservation Monitoring Centre
five years earlier, which classified N. muluensis as "endangered
". In 1997, Charles Clarke
informally classified the species as Endangered
based on the IUCN
criteria, noting that it is Conservation Dependent
if populations in protected areas are taken into account.
and Sulawesi
: N. glabrata
, N. hamata
, N. murudensis
, and N. tentaculata
.
Nepenthes muluensis is most easily confused with N. tentaculata. The lower pitchers of these species are almost identical, but those of N. muluensis have a rounder mouth. The climbing stem, growth habit and leaves are also similar, although N. muluensis usually has a narrower lamina. However, the upper pitchers of N. muluensis are distinctive; they usually have a white lid, a round mouth, and their wings are either greatly reduced or absent altogether.
× N. muluensis and N. muluensis × N. tentaculata
.
in 1993 by J. H. Adam
, C. C. Wilcock
, and M. D. Swaine. The authors distinguished the taxon
from N. muluensis on the basis of its branched spur
and the presence of fringe hairs on the top of the lid. They also compared the distribution of phenol
ic compounds
in the leaves of N. muluensis and the hybrid, although they did so without specifying the number of plants studied or the number of repetitions performed. As a result, doubts have been raised over the existence of this hybrid. Charles Clarke
writes that the authors described N. × sarawakiensis "in such a way that their work cannot be easily repeated". Although this natural hybrid is likely to exist, it is possible that N. × sarawakiensis was described based on specimens of N. muluensis with lower pitchers.
In 2002, phytochemical screening
and analytical chromatography were used to study the presence of phenolic compounds and leucoanthocyanins in N. × sarawakiensis and its putative parent species. The research was based on leaf material from dry herbarium specimens. Eight spots containing phenolic acid
s, flavonols, flavones, leucoanthocyanins and 'unknown flavonoid
s' 1 and 3 were identified from chromatographic profiles. The distributions of these in N. × sarawakiensis, N. muluensis and N. tentaculata are shown in the table to the left. A specimen of N. × sarawakiensis grown from tissue culture
(in vitro
) was also tested.
Phenolic acid, 'Unknown Flavonoid 1' and cyanidin
were undetected in N. muluensis, while N. tentaculata lacked quercetin
, luteolin
, 'Unknown Flavonoid 3', and cyanidin. Chromatographic patterns of the N. × sarawakiensis samples studied showed complementation of its putative parental species.
Myricetin
was found to be absent from all studied taxa. This agrees with the findings of previous authors and suggests that the absence of a widely distributed compound like myricetin among the Nepenthes examined might provide additional diagnostic information for these taxa
.
Pitcher plant
Pitcher plants are carnivorous plants whose prey-trapping mechanism features a deep cavity filled with liquid known as a pitfall trap. It has been widely assumed that the various sorts of pitfall trap evolved from rolled leaves, with selection pressure favouring more deeply cupped leaves over...
endemic to Borneo
Borneo
Borneo is the third largest island in the world and is located north of Java Island, Indonesia, at the geographic centre of Maritime Southeast Asia....
. It grows in highland habitats at elevations of 1700 to 2400 m above sea level.
Botanical history
Nepenthes muluensis was first collected by Mitsuru HottaMitsuru Hotta
is a Japanese botanist best known for his research on Araceae.Hotta was born in Osaka, Japan in 1937. He graduated from the Agricultural Department of Osaka Prefecture University in 1960. The same year, he took part in the Tonga and Fiji Expedition organised by Kyoto University...
on March 18, 1964, on Mardi between the third and fourth camps on the western ridge of Mount Mulu
Mount Mulu
Mount Mulu is a sandstone and shale mountain. At 2376 m, it is the second highest mountain in the state of Sarawak, after Mount Murud. It is located within the boundaries of Gunung Mulu National Park, which is named after it....
. The holotype
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
, M.Hotta 14791d, is deposited at the Botany Department of Kyoto University
Kyoto University
, or is a national university located in Kyoto, Japan. It is the second oldest Japanese university, and formerly one of Japan's Imperial Universities.- History :...
(KYO). Hotta described the species in 1966, naming it after Mount Mulu
Mount Mulu
Mount Mulu is a sandstone and shale mountain. At 2376 m, it is the second highest mountain in the state of Sarawak, after Mount Murud. It is located within the boundaries of Gunung Mulu National Park, which is named after it....
, to which it was thought to be endemic. The description did not cover the lower pitchers of this species, which were unknown at the time. Nepenthes muluensis was the first Nepenthes species to be described in 26 years (after N. densiflora
Nepenthes densiflora
Nepenthes densiflora is a tropical pitcher plant endemic to Sumatra, where it grows at an altitude of between 1700 and 3200 m above sea level.No forms or varieties of N. densiflora have been described.-Taxonomy:...
in 1940) and the first since the end of World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
. At this time the genus was experiencing a revival in global interest, thanks largely to the work of Shigeo Kurata
Shigeo Kurata
is a Japanese botanist and Nepenthes taxonomist whose work in the 1960s and 1970s contributed much to the current popularity of these plants. Of particular note is his 1976 guide, Nepenthes of Mount Kinabalu....
.
Nepenthes muluensis has been misidentified at least once in the literature; Bertram Evelyn Smythies identified specimens of N. muluensis as belonging to N. gracillima
Nepenthes gracillima
Nepenthes gracillima is a highland Nepenthes pitcher plant species, native to Peninsular Malaysia.-Infraspecific taxa:*Nepenthes gracillima f. ramispina Hort.Westphal [=N. ramispina]...
, a species endemic to Peninsular Malaysia
Peninsular Malaysia
Peninsular Malaysia , also known as West Malaysia , is the part of Malaysia which lies on the Malay Peninsula. Its area is . It shares a land border with Thailand in the north. To the south is the island of Singapore. Across the Strait of Malacca to the west lies the island of Sumatra...
. This misidentification was published in 1965 in the proceedings of the UNESCO Humid Tropics Symposium, which was held in Kuching
Kuching
Kuching , officially the City of Kuching, and formerly the City of Sarawak, is the capital and most populous city of the East Malaysian state of Sarawak. It is the largest city on the island of Borneo, and the fourth largest city in Malaysia....
two years earlier.
Description
Nepenthes muluensis is a climbing plant. The stem may attain a length of 4 m and is up to 5 mm in diameter. InternodePlant stem
A stem is one of two main structural axes of a vascular plant. The stem is normally divided into nodes and internodes, the nodes hold buds which grow into one or more leaves, inflorescence , conifer cones, roots, other stems etc. The internodes distance one node from another...
s are cylindrical in cross section and up to 8 cm long.
The leaves of this species are coriaceous and sessile. The lamina is lanceolate in shape and up to 8 cm long by 1.5 cm wide. It usually has an acute apex and is gradually attenuate towards the base, extending into an amplexicaul sheath. Up to 4 longitudinal veins are present on either side of the midrib. Pinnate veins are numerous but indistinct. Tendril
Tendril
In botany, a tendril is a specialized stem, leaf or petiole with a threadlike shape that is used by climbing plants for support, attachment and cellular invasion by parasitic plants, generally by twining around suitable hosts. They do not have a lamina or blade, but they can photosynthesize...
s are up to 8 cm long.
Rosette and lower pitchers are up to 7 cm high and 3 cm wide. They are ovate in the lower third, becoming cylindrical or conical above. The peristome
Peristome
The word peristome is derived from the Greek peri, meaning 'around' or 'about', and stoma, 'mouth'. It is a term used to describe various anatomical features that surround an opening to an organ or structure. The term is used in plants and invertebrate animals, such as in describing the shells of...
is approximately cylindrical and up to 5 mm wide. Its inner margin is lined with small but distinct teeth. The pitcher mouth is round to ovate and has an oblique insertion. The lid or operculum
Operculum (botany)
An operculum, in botany, is a term generally used to describe a structure within a plant, moss, or fungus acting as a cap, flap, or lid. In plants, it may also be called a bud cap.Examples of structures identified as opercula include:...
is ovate and generally obtuse. It bears a number of filiform appendages (≤5 mm long) on its upper surface.
Upper pitchers are cylindrical and often bulbous in the lowermost part. Like their lower counterparts, they are relatively small, reaching only 10 cm in height and 2 cm in width. They have a pair of ribs in place of wings. The pitcher mouth is round and bears a cylindrical peristome up to 3 mm wide. The lid is orbicular and lacks appendages. An unbranched spur
Spur (biology)
A spur in botany is a spike, usually part of a flower.In certain plants, part of a sepal or petal develops into an elongated hollow spike extending behind the flower, containing nectar which is sucked by long-tongued animals . Plants with such structures include Delphinium, Aquilegia, Piperia, and...
in inserted near the base of the lid.
Nepenthes muluensis has a racemose
Raceme
A raceme is a type of inflorescence that is unbranched and indeterminate and bears pedicellate flowers — flowers having short floral stalks called pedicels — along the axis. In botany, axis means a shoot, in this case one bearing the flowers. In a raceme, the oldest flowers are borne...
inflorescence
Inflorescence
An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...
. It is very compact: the peduncle
Peduncle (botany)
In botany, a peduncle is a stem supporting an inflorescence, or after fecundation, an infructescence.The peduncle is a stem, usually green and without leaves, though sometimes colored or supporting small leaves...
is only up to 3 cm long, while the attenuate rachis
Rachis
Rachis is a biological term for a main axis or "shaft".-In zoology:In vertebrates a rachis can refer to the series of articulated vertebrae, which encase the spinal cord. In this case the rachis usually form the supporting axis of the body and is then called the spine or vertebral column...
reaches 10 cm in length. Pedicels
Pedicel (botany)
A pedicel is a stem that attaches single flowers to the main stem of the inflorescence. It is the branches or stalks that hold each flower in an inflorescence that contains more than one flower....
are up to 5 mm long and lack bract
Bract
In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis, or cone scale. Bracts are often different from foliage leaves. They may be smaller, larger, or of a different color, shape, or texture...
s. Sepal
Sepal
A sepal is a part of the flower of angiosperms . Collectively the sepals form the calyx, which is the outermost whorl of parts that form a flower. Usually green, sepals have the typical function of protecting the petals when the flower is in bud...
s are ovate and up to 2 mm long. A study of 120 pollen
Pollen
Pollen is a fine to coarse powder containing the microgametophytes of seed plants, which produce the male gametes . Pollen grains have a hard coat that protects the sperm cells during the process of their movement from the stamens to the pistil of flowering plants or from the male cone to the...
samples taken from two herbarium specimens (J.H.Adam 2401 and J.H.Adam 2405) found the mean pollen diameter to be 32.0 μm
Micrometre
A micrometer , is by definition 1×10-6 of a meter .In plain English, it means one-millionth of a meter . Its unit symbol in the International System of Units is μm...
(SE
Standard error (statistics)
The standard error is the standard deviation of the sampling distribution of a statistic. The term may also be used to refer to an estimate of that standard deviation, derived from a particular sample used to compute the estimate....
= 0.4; CV
Coefficient of variation
In probability theory and statistics, the coefficient of variation is a normalized measure of dispersion of a probability distribution. It is also known as unitized risk or the variation coefficient. The absolute value of the CV is sometimes known as relative standard deviation , which is...
= 8.7%).
The species completely lacks an indumentum
Indumentum
The indumentum is a covering of fine hairs or bristles on a plant or insect.In plants, the indumentum types are:*pubescent*hirsute*pilose*villous*tomentose*stellate*scabrous*scurfy...
, with all parts of the plant being glabrous.
The type population of N. muluensis from Mount Mulu
Mount Mulu
Mount Mulu is a sandstone and shale mountain. At 2376 m, it is the second highest mountain in the state of Sarawak, after Mount Murud. It is located within the boundaries of Gunung Mulu National Park, which is named after it....
has a distinctive pitcher colouration. Lower pitchers are generally dark purple with sparse yellow speckles. The upper pitchers of this form are usually purple with numerous yellowish-white speckles. They often have a white peristome and lid. Plants from Mount Murud
Mount Murud
Mount Murud or Muru is a sandstone mountain located in the Malaysian part of Borneo. At 2,423 m , it is the highest mountain in the state of Sarawak....
produce darker-coloured pitchers.
Ecology
As its name suggests, N. muluensis was originally known only from Mount MuluMount Mulu
Mount Mulu is a sandstone and shale mountain. At 2376 m, it is the second highest mountain in the state of Sarawak, after Mount Murud. It is located within the boundaries of Gunung Mulu National Park, which is named after it....
. However, since its description it has also been recorded from several other mountains, including Mount Murud
Mount Murud
Mount Murud or Muru is a sandstone mountain located in the Malaysian part of Borneo. At 2,423 m , it is the highest mountain in the state of Sarawak....
and Bukit Batu Lawi
Bukit Batu Lawi
Bukit Batu Lawi is a mountain located in the Malaysian part of Borneo. At 2,046 m , it is one of the highest mountains in the state of Sarawak.- Further reading :* Lightner, Sam Jr. All Elevations Unknown...
. Nepenthes muluensis has not been recorded from the nearby summits of Mount Api
Mount Api
Mount Api is a limestone mountain located in Gunung Mulu National Park in Sarawak, Malaysia. Neighbouring Mount Benarat and Mount Buda are part of the same formation...
and Mount Benarat, although these are limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
peaks and mostly lie outside the known altitudinal distribution of the species, which is 1700 to 2400 m above sea level.
Nepenthes muluensis grows in nutrient-deficient soils of the upper montane zone. It typically occurs in open areas of mossy forest amongst ridge-top vegetation. On Mount Mulu, the species seems to be restricted to the western ridge and occurs from an elevation of around 1900 m to the summit at 2376 m. The summit vegetation is greatly stunted, rarely exceeding a metre in height. It is dominated by rhododendron
Rhododendron
Rhododendron is a genus of over 1 000 species of woody plants in the heath family, most with showy flowers...
s (particularly Rhododendron ericoides), as well as species of the genera Diplycosia and Vaccinium
Vaccinium
Vaccinium is a genus of shrubs or dwarf shrubs in the plant Family Ericaceae. The fruit of many species are eaten by humans and some are of commercial importance, including the cranberry, blueberry, bilberry or whortleberry, lingonberry or cowberry, and huckleberry...
. Nepenthes muluensis is most abundant in summit heath forest
Heath forest
Heath forest is a type of tropical moist forest found in areas with acidic, sandy soils that are extremely nutrient-poor. Notable examples are the Rio Negro campinarana of the Amazon Basin in South America, and the Sundaland heath forests of Borneo and neighboring islands.-External links:**...
, where it forms dense stands with hundreds of white-speckled pitchers suspended over the sympatric shrubs.
On Mount Murud, N. muluensis grows in shady mossy forest. This population produces darker pitchers than the one from Mount Mulu, possibly due to greater exposure to ultraviolet
Ultraviolet
Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...
light at higher altitudes. Two true toad
True toad
Bufonidae is the family of the true toads, members of the order Anura . They are the only family of anurans all members of which are known as "toads." The bufonids now comprise more than 35 genera, Bufo being the most widespread and well known.-Characteristics:True toads are widespread and occur...
species from Mount Murud, Pelophryne linanitensis
Pelophryne linanitensis
Pelophryne linanitensis is a species of toad in the Bufonidae family. It is endemic to Borneo....
and Pelophryne murudensis
Pelophryne murudensis
Pelophryne murudensis is a species of toad in the Bufonidae family. It is endemic to Borneo....
, are sympatric with N. muluensis and may breed in its pitchers.
The conservation status
Conservation status
The conservation status of a group of organisms indicates whether the group is still extant and how likely the group is to become extinct in the near future...
of N. muluensis is listed as Vulnerable
Vulnerable species
On 30 January 2010, the IUCN Red List of Threatened Species identified 9694 Vulnerable species, subspecies and varieties, stocks and sub-populations.-References:...
on the 2006 IUCN Red List of Threatened Species
IUCN Red List
The IUCN Red List of Threatened Species , founded in 1963, is the world's most comprehensive inventory of the global conservation status of biological species. The International Union for Conservation of Nature is the world's main authority on the conservation status of species...
based on an assessment carried out in 2000. This differs from the assessment made by the World Conservation Monitoring Centre
World Conservation Monitoring Centre
The United Nations Environment Programme's World Conservation Monitoring Centre is an executive agency of the United Nations Environment Programme, based in Cambridge in the United Kingdom. UNEP-WCMC has been part of UNEP since 2000, and has responsibility for biodiversity assessment and support...
five years earlier, which classified N. muluensis as "endangered
Endangered species
An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...
". In 1997, Charles Clarke
Charles Clarke (botanist)
Dr. Charles M. Clarke is a botanist and taxonomist specialising in the carnivorous plant genus Nepenthes. Clarke has an honours degree in Botany from Monash University in Melbourne, and a Ph.D. in Ecosystem Management at the University of New England, in Armidale, New South Wales.Clarke first...
informally classified the species as Endangered
Endangered species
An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...
based on the IUCN
World Conservation Union
The International Union for Conservation of Nature and Natural Resources is an international organization dedicated to finding "pragmatic solutions to our most pressing environment and development challenges." The organization publishes the IUCN Red List, compiling information from a network of...
criteria, noting that it is Conservation Dependent
Conservation Dependent
Conservation Dependent was an IUCN category assigned to species or lower taxa which were dependent on conservation efforts to prevent the taxon becoming threatened with extinction...
if populations in protected areas are taken into account.
Related species
Nepenthes muluensis belongs to what has been called the "Hamata group", which also includes four other closely related species from BorneoBorneo
Borneo is the third largest island in the world and is located north of Java Island, Indonesia, at the geographic centre of Maritime Southeast Asia....
and Sulawesi
Sulawesi
Sulawesi is one of the four larger Sunda Islands of Indonesia and is situated between Borneo and the Maluku Islands. In Indonesia, only Sumatra, Borneo, and Papua are larger in territory, and only Java and Sumatra have larger Indonesian populations.- Etymology :The Portuguese were the first to...
: N. glabrata
Nepenthes glabrata
Nepenthes glabrata is a tropical pitcher plant endemic to Sulawesi. The species grows in open, high forest at elevations of 1600 to 2100 m. It produces dainty, colourful pitchers reaching only a few centimetres in height...
, N. hamata
Nepenthes hamata
Nepenthes hamata is a tropical pitcher plant endemic to Sulawesi, where it grows at elevations of 1400–2500 m above sea level.The specific epithet hamata is derived from the Latin word hamatus, meaning "hooked"...
, N. murudensis
Nepenthes murudensis
Nepenthes murudensis , or the Murud Pitcher-Plant, is a tropical pitcher plant endemic to Mount Murud in Borneo, after which it is named. It is of putative hybrid origin: its two original parent species are thought to be N. reinwardtiana and N...
, and N. tentaculata
Nepenthes tentaculata
Nepenthes tentaculata , or the Fringed Pitcher-Plant, is a tropical pitcher plant with a very wide distribution across Borneo and Sulawesi...
.
Nepenthes muluensis is most easily confused with N. tentaculata. The lower pitchers of these species are almost identical, but those of N. muluensis have a rounder mouth. The climbing stem, growth habit and leaves are also similar, although N. muluensis usually has a narrower lamina. However, the upper pitchers of N. muluensis are distinctive; they usually have a white lid, a round mouth, and their wings are either greatly reduced or absent altogether.
Natural hybrids
Two natural hybrids involving N. muluensis have been recorded: N. lowiiNepenthes lowii
Nepenthes lowii , or Low's Pitcher-Plant, is a tropical pitcher plant endemic to Borneo. It is named after Hugh Low, who discovered it on Mount Kinabalu...
× N. muluensis and N. muluensis × N. tentaculata
Nepenthes tentaculata
Nepenthes tentaculata , or the Fringed Pitcher-Plant, is a tropical pitcher plant with a very wide distribution across Borneo and Sulawesi...
.
Nepenthes × sarawakensis
Nepenthes muluensis × N. tentaculata was described as N. × sarawakiensisNepenthes × sarawakiensis
Nepenthes × sarawakiensis is a natural hybrid involving N. muluensis and N. tentaculata. It is quite a rare plant as one of its parent species, N. muluensis, is only known from several isolated mountains.-References:...
in 1993 by J. H. Adam
J. H. Adam
Jumaat Haji Adam is a botanist and taxonomist specialising in the carnivorous pitcher plant genus Nepenthes.Adam has described numerous Nepenthes taxa, mostly with C. C. Wilcock, including the species N. faizaliana and N. mapuluensis, as well as the natural hybrids N. × alisaputrana, N. ×...
, C. C. Wilcock
C. C. Wilcock
Christopher C. Wilcock is a taxonomist specialising in the carnivorous pitcher plant genus Nepenthes.Together with J. H. Adam, Wilcock has described several Nepenthes taxa, including the species N. faizaliana and N. mapuluensis, as well as the natural hybrids N. × alisaputrana and N. ×...
, and M. D. Swaine. The authors distinguished the taxon
Taxon
|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...
from N. muluensis on the basis of its branched spur
Spur (biology)
A spur in botany is a spike, usually part of a flower.In certain plants, part of a sepal or petal develops into an elongated hollow spike extending behind the flower, containing nectar which is sucked by long-tongued animals . Plants with such structures include Delphinium, Aquilegia, Piperia, and...
and the presence of fringe hairs on the top of the lid. They also compared the distribution of phenol
Natural phenol
Natural phenols, bioavailable phenols, plant phenolics, low molecular weight phenols or phenoloids are a class of natural products. They are small molecules containing one or more phenolic group. These molecules are smaller in size than polyphenols, containing less than 12 phenolic groups...
ic compounds
Chemical compound
A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...
in the leaves of N. muluensis and the hybrid, although they did so without specifying the number of plants studied or the number of repetitions performed. As a result, doubts have been raised over the existence of this hybrid. Charles Clarke
Charles Clarke (botanist)
Dr. Charles M. Clarke is a botanist and taxonomist specialising in the carnivorous plant genus Nepenthes. Clarke has an honours degree in Botany from Monash University in Melbourne, and a Ph.D. in Ecosystem Management at the University of New England, in Armidale, New South Wales.Clarke first...
writes that the authors described N. × sarawakiensis "in such a way that their work cannot be easily repeated". Although this natural hybrid is likely to exist, it is possible that N. × sarawakiensis was described based on specimens of N. muluensis with lower pitchers.
| Distribution of phenolic compounds and leucoanthocyanins in N. muluensis, N. tentaculata, and N. × sarawakiensis |
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| Taxon | Specimen | ||||||||
| N. muluensis | Jumaat 2400 | ||||||||
| N. tentaculata Nepenthes tentaculata Nepenthes tentaculata , or the Fringed Pitcher-Plant, is a tropical pitcher plant with a very wide distribution across Borneo and Sulawesi... |
Jumaat 2392 | ||||||||
| N. × sarawakiensis Nepenthes × sarawakiensis Nepenthes × sarawakiensis is a natural hybrid involving N. muluensis and N. tentaculata. It is quite a rare plant as one of its parent species, N. muluensis, is only known from several isolated mountains.-References:... |
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| N. × sarawakiensis (in vitro In vitro In vitro refers to studies in experimental biology that are conducted using components of an organism that have been isolated from their usual biological context in order to permit a more detailed or more convenient analysis than can be done with whole organisms. Colloquially, these experiments... ) |
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| Key: 1: Phenolic acid Phenolic acid Phenolic acids are a type of organic compounds. Included in that class are substances containing a phenolic ring and an organic carboxylic acid function .... , 2: Ellagic acid Ellagic acid Ellagic acid is a natural phenol antioxidant found in numerous fruits and vegetables including blackberries, raspberries, strawberries, cranberries, walnuts, pecans, pomegranates, wolfberry and other plant foods... , 3: Quercetin Quercetin Quercetin , a flavonol, is a plant-derived flavonoid found in fruits, vegetables, leaves and grains. It also may be used as an ingredient in supplements, beverages or foods.-Occurrence:... , 4: Kaempferol Kaempferol Kaempferol is a natural flavonol, a type of flavonoid, that has been isolated from tea, broccoli, Delphinium, Witch-hazel, grapefruit,cabbage, kale, beans, endive, leek, tomato, strawberries, grapes, brussels sprouts, apples and other plant sources. Kaempferol is a yellow crystalline solid with a... , 5: Luteolin Luteolin Luteolin is a yellow crystalline compound. It is a flavonoid; to be specific, it is one of the more common flavones. From preliminary research, it is thought to play a role in the human body possibly as an antioxidant, a free radical scavenger, a promoter of carbohydrate metabolism, or an immune... , 6: 'Unknown Flavonoid Flavonoid Flavonoids , are a class of plant secondary metabolites.... 1', 7: 'Unknown Flavonoid 3', 8: Cyanidin Cyanidin Cyanidin is a natural organic compound. It is a particular type of anthocyanidin . It is a pigment found in many red berries including but not limited to grapes, bilberry, blackberry, blueberry, cherry, cranberry, elderberry, hawthorn, loganberry, acai berry and raspberry... ±: very weak spot, +: weak spot, ++: strong spot, 3+: very strong spot, -: absent |
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In 2002, phytochemical screening
Phytochemical
Phytochemicals are biologically active chemical compounds that occur naturally in plants . Phytochemicals are the molecules responsible for the color and organoleptic properties . For example, the deep purple color of blueberries and the smell of garlic...
and analytical chromatography were used to study the presence of phenolic compounds and leucoanthocyanins in N. × sarawakiensis and its putative parent species. The research was based on leaf material from dry herbarium specimens. Eight spots containing phenolic acid
Phenolic acid
Phenolic acids are a type of organic compounds. Included in that class are substances containing a phenolic ring and an organic carboxylic acid function ....
s, flavonols, flavones, leucoanthocyanins and 'unknown flavonoid
Flavonoid
Flavonoids , are a class of plant secondary metabolites....
s' 1 and 3 were identified from chromatographic profiles. The distributions of these in N. × sarawakiensis, N. muluensis and N. tentaculata are shown in the table to the left. A specimen of N. × sarawakiensis grown from tissue culture
Tissue culture
Tissue culture is the growth of tissues or cells separate from the organism. This is typically facilitated via use of a liquid, semi-solid, or solid growth medium, such as broth or agar...
(in vitro
In vitro
In vitro refers to studies in experimental biology that are conducted using components of an organism that have been isolated from their usual biological context in order to permit a more detailed or more convenient analysis than can be done with whole organisms. Colloquially, these experiments...
) was also tested.
Phenolic acid, 'Unknown Flavonoid 1' and cyanidin
Cyanidin
Cyanidin is a natural organic compound. It is a particular type of anthocyanidin . It is a pigment found in many red berries including but not limited to grapes, bilberry, blackberry, blueberry, cherry, cranberry, elderberry, hawthorn, loganberry, acai berry and raspberry...
were undetected in N. muluensis, while N. tentaculata lacked quercetin
Quercetin
Quercetin , a flavonol, is a plant-derived flavonoid found in fruits, vegetables, leaves and grains. It also may be used as an ingredient in supplements, beverages or foods.-Occurrence:...
, luteolin
Luteolin
Luteolin is a yellow crystalline compound. It is a flavonoid; to be specific, it is one of the more common flavones. From preliminary research, it is thought to play a role in the human body possibly as an antioxidant, a free radical scavenger, a promoter of carbohydrate metabolism, or an immune...
, 'Unknown Flavonoid 3', and cyanidin. Chromatographic patterns of the N. × sarawakiensis samples studied showed complementation of its putative parental species.
Myricetin
Myricetin
Myricetin is a naturally occurring flavonol, a flavonoid found in many grapes, berries, fruits, vegetables, herbs, as well as other plants. Walnuts are a rich dietary source. Trace amounts can be found as glycosides. It is one of the phenolic compounds present in red wine.Myricetin has antioxidant...
was found to be absent from all studied taxa. This agrees with the findings of previous authors and suggests that the absence of a widely distributed compound like myricetin among the Nepenthes examined might provide additional diagnostic information for these taxa
Taxon
|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...
.
External links
- Nepenthes muluensis at ARKiveARKiveARKive is a global initiative with the mission of "promoting the conservation of the world's threatened species, through the power of wildlife imagery", which it does by locating and gathering films, photographs and audio recordings of the world's species into a centralised digital archive. Its...