Nepenthes insignis
Encyclopedia
Nepenthes insignis is a tropical pitcher plant
endemic to New Guinea
and surrounding islands. The specific epithet insignis is Latin
for "distinguished" or "remarkable".
on November 9, 1912. The specimen, Pulle 277, was collected in southwestern New Guinea
at the "[b]order of the Beaufort River" at an altitude of 80 m. It includes male floral material and is deposited at the Bogor Botanical Gardens
(formerly the Herbarium of the Buitenzorg Botanic Gardens) in Java
. It is also preserved in alcohol
and is sheet 201110 at the National Herbarium of the Netherlands
in Leiden.
Nepenthes insignis was collected again in September 1926, by Willem Marius Docters van Leeuwen. The specimens, Docters van Leeuwen 10258 and 10286, were collected in northwestern New Guinea at the "[b]order of affluent C of the Rouffaer River" at an altitude of 250 m. They are also deposited at the Bogor Botanical Gardens, although they do not include floral material.
B. H. Danser
formally described
N. insignis in his seminal monograph "The Nepenthaceae of the Netherlands Indies
", published in 1928. The description was based solely on herbarium material and Danser did not see the species in its natural habitat. Danser designated Pulle 277 as the type specimen.
Two further collections of N. insignis were made by Leonard John Brass
in March 1939, 4 km south west of Bernhard Camp, Idenburg River (sheet 13379) and 8 km south west of Bernhard Camp (sheet 13669). Both are deposited at the Bogor Botanical Gardens.
It appears that N. insignis was knowingly observed in the wild only in 1994 by four members of a field trip to New Guinea: W. Baumgartl, B. Kistler, H. Rischer, and A. Wistuba
. A report on the group's findings was published in the Carnivorous Plant Newsletter
the following year.
are triangular in cross section and up to 9 cm long.
Leaves are coriaceous and sessile. The lamina is linear-lanceolate or slightly spathulate and up to 35 cm long and 6 cm wide. It has an acute apex and is gradually attenuate towards the base. Four to six longitudinal veins are present on either side of the midrib. Pinnate veins run obliquely towards the margin and are indistinct in the outer part of the lamina. Tendril
s are up to 6 mm in diameter and may or may not have a curl.
Rosette and lower pitchers are ovate or narrowly ovate in the lower half and cylindrical above. They can be very large, reaching 35 cm in height. Terrestrial pitchers usually lack fringed wings, having a pair of ribs instead. The insertion of the pitcher mouth is slightly oblique. The flattened peristome
bears ribs spaced 0.5 to 1 mm apart. Its inner margin is lined with small teeth up to 1 mm long. It is not elongated into a neck. The inner surface of the pitcher is glandular in its lower half. Digestive glands are present at a density of 150 to 1500 per square centimetre. The pitcher lid is orbiculate to broad cordate, bears a distinct midline, and may be up to 8 cm long. Numerous large glands are present on the underside of the lid, concentrated near the two main lateral veins. An unbranched filiform spur
(≤5 mm long) is inserted near the base of the lid.
Upper pitchers gradually arise from the ends of the tendrils, forming a 5 to 35 mm wide curve. They are infundibulate in the lower part and cylindrical above. They are up to 30 cm high and 8 cm wide. They may have very short wings (≤3 cm long) below the peristome. The pitcher mouth is oblique and acute or acuminate towards the lid. The expanded peristome is up to 35 mm wide and bears ribs spaced 0.5 to 1 mm apart. Its inner margin is lined with teeth which are about as long as they are wide. The inner surface of the pitcher is almost wholly glandular. The very small, overarched digestive glands occur at a density of 400 to 3000 per square centimetre. The pitcher lid is orbicular-ovate and up to 7.5 cm long. It bears a distinct midline and two distinct lateral veins. A number of large suborbicular glands are concentrated around these veins. A filiform spur (≤5 mm long) is inserted near the base of the lid.
Nepenthes insignis has a racemose
inflorescence
. The peduncle
is up to 18 cm long and 7 mm in diameter. The rachis
is attenuate, angular in cross section, and up to 46 cm long. Pedicels
are two-flowered and lack bract
s. They may be up to 22 mm long. The oblong tepal
s are approximately 4 mm long. Stamen
s are around 5 mm long including the anthers.
Most parts of the plant are virtually glabrous. Developing pitchers have a sparse indumentum
of short stellate hairs. Developing inflorescences are very densely hairy, becoming less hairy when mature. Pedicels and tepals are densely and shortly hairy. Stamens are more densely hairy near the base than near the anthers.
The stem and lamina are green. Lower pitchers are usually dark green with red blotches concentrated near the peristome, which is dark reddish-brown. Upper pitchers are yellowish-green with fewer blotches. Herbarium specimens are greenish or yellowish to light brown in colour. Faint red spots are visible on the outside surface of preserved pitchers. In dried specimens, the non-glandular portion of the inner surface is bluish and pruinose and may or may not be spotted.
Nepenthes insignis is endemic to Western New Guinea
and a number of nearby islands in Cenderawasih Bay
. It has an altitudinal distribution of 0–850 m above sea level. In the southern part of the Lake Plains region of New Guinea it has been recorded from elevations of between 115 and 800 m. A smaller form of this species is also found near sea-level on the island of Biak
.
Nepenthes insignis occurs in dense forest and on foothills. Plants usually grow epiphytically
in thick layers of moss, especially in trees overhanging rivers. At higher altitudes, the species has also been recorded from sediment bars along rivers. Relative humidity
is always high in these habitats; the seeds of one plant which grew near a small waterfall were found to have germinated
while still in their capsules.
In its natural habitat, N. insignis occurs sympatrically with N. ampullaria
, N. maxima
(above 400 m altitude), N. mirabilis
, and plants tentatively identified as N. papuana
that grow at 575 m altitude. One natural hybrid with N. mirabilis has been recorded.
Nepenthes insignis is listed as Vulnerable
on the 2006 IUCN Red List of Threatened Species
.
es. It has been suggested that these nocturnal insects are attracted by odour produced by the plant.
Nepenthes insignis has been used in a study concerning the carnivory of Nepenthes and their production of the allelochemical plumbagin
. It was shown that L-alanine
fed in vitro
to the pitchers of N. insignis is used to build up plumbagin, but is not incorporated into rossoliside and plumbaside A. The results suggest that these compounds are used for storage and have very low turnover rates.
suggested that N. insignis is related to N. merrilliana
from the Philippines
. He placed both species in the Insignes
clade
, the members of which are characterised by coarse stems, large leaves, sparse indumentums, sessile leaves, and lids without appendages.
Nepenthes insignis has also been compared to N. sibuyanensis
, another Philippine endemic. It can be distinguished from that species on the basis of a number of morphological features. The former produces two-flowered pedicels
, whereas those of N. sibuyanensis are one-flowered. The pitcher mouth of N. insignis is oblique, compared to almost horizontal in the latter. In addition, the peristome of N. sibuyanensis forms a short neck, while N. insignis lacks a neck completely. Furthermore, N. insignis has shorter peristome teeth than N. sibuyanensis (1 mm versus 5 mm). The pitchers of N. sibuyanensis also differ in shape, being ovate or slightly infundibulate.
was found by members of the 1994 field trip to New Guinea. The plant was growing at an altitude of around 500 m.
In Papua, N. insignis is commonly sympatric with N. ampullaria
and N. maxima
, and hybrids involving these species may also occur, although none have been recorded to date.
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 New Guinea
New Guinea
New Guinea is the world's second largest island, after Greenland, covering a land area of 786,000 km2. Located in the southwest Pacific Ocean, it lies geographically to the east of the Malay Archipelago, with which it is sometimes included as part of a greater Indo-Australian Archipelago...
and surrounding islands. The specific epithet insignis is Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
for "distinguished" or "remarkable".
Botanical history
The first known collection of N. insignis was made by August Adriaan PulleAugust Adriaan Pulle
August Adrian Pulle was a Dutch professor and botanist. He made important contributions to knowledge of the Flora of Suriname and the island of New Guinea.-Education:...
on November 9, 1912. The specimen, Pulle 277, was collected in southwestern New Guinea
New Guinea
New Guinea is the world's second largest island, after Greenland, covering a land area of 786,000 km2. Located in the southwest Pacific Ocean, it lies geographically to the east of the Malay Archipelago, with which it is sometimes included as part of a greater Indo-Australian Archipelago...
at the "[b]order of the Beaufort River" at an altitude of 80 m. It includes male floral material and is deposited at the Bogor Botanical Gardens
Bogor Botanical Gardens
The Bogor Botanical Gardens are located 60 km south of the capital of Jakarta in Bogor, Indonesia. The botanical gardens are situated in the city center of Bogor and adjoin the Istana Bogor...
(formerly the Herbarium of the Buitenzorg Botanic Gardens) in Java
Java
Java is an island of Indonesia. With a population of 135 million , it is the world's most populous island, and one of the most densely populated regions in the world. It is home to 60% of Indonesia's population. The Indonesian capital city, Jakarta, is in west Java...
. It is also preserved in alcohol
Alcohol
In chemistry, an alcohol is an organic compound in which the hydroxy functional group is bound to a carbon atom. In particular, this carbon center should be saturated, having single bonds to three other atoms....
and is sheet 201110 at the National Herbarium of the Netherlands
National Herbarium of the Netherlands
The National Herbarium of the Netherlands was established in 1999 through a decentralized merger of the major university herbaria of Leiden , Utrecht and Wageningen...
in Leiden.
Nepenthes insignis was collected again in September 1926, by Willem Marius Docters van Leeuwen. The specimens, Docters van Leeuwen 10258 and 10286, were collected in northwestern New Guinea at the "[b]order of affluent C of the Rouffaer River" at an altitude of 250 m. They are also deposited at the Bogor Botanical Gardens, although they do not include floral material.
B. H. Danser
B. H. Danser
Benedictus Hubertus Danser , often abbreviated B. H. Danser, was a Dutch taxonomist and botanist...
formally described
Species description
A species description or type description is a formal description of a newly discovered species, usually in the form of a scientific paper. Its purpose is to give a clear description of a new species of organism and explain how it differs from species which have been described previously, or are...
N. insignis in his seminal monograph "The Nepenthaceae of the Netherlands Indies
The Nepenthaceae of the Netherlands Indies
"The Nepenthaceae of the Netherlands Indies" is a seminal monograph by B. H. Danser on the tropical pitcher plants of the Dutch East Indies, North Borneo, the Malay Peninsula, and eastern New Guinea...
", published in 1928. The description was based solely on herbarium material and Danser did not see the species in its natural habitat. Danser designated Pulle 277 as the type specimen.
Two further collections of N. insignis were made by Leonard John Brass
Leonard John Brass
Leonard John Brass was an Australian and American botanist, botanical collector and explorer. He was born at Toowoomba, Queensland...
in March 1939, 4 km south west of Bernhard Camp, Idenburg River (sheet 13379) and 8 km south west of Bernhard Camp (sheet 13669). Both are deposited at the Bogor Botanical Gardens.
It appears that N. insignis was knowingly observed in the wild only in 1994 by four members of a field trip to New Guinea: W. Baumgartl, B. Kistler, H. Rischer, and A. Wistuba
Andreas Wistuba
Dr. Andreas Wistuba is a German taxonomist and botanist specialising in the carnivorous plant genera Heliamphora and Nepenthes. More than half of all known Heliamphora species have been described by Wistuba.-Publications:...
. A report on the group's findings was published in the Carnivorous Plant Newsletter
Carnivorous Plant Newsletter
The Carnivorous Plant Newsletter is the official publication of the International Carnivorous Plant Society , the largest such organization in the world.-History and editorship:...
the following year.
Description
Nepenthes insignis is a weak climber. The stem is usually around 50 to 80 cm long and up to 7 mm in diameter. InternodesPlant 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...
are triangular in cross section and up to 9 cm long.
Leaves are coriaceous and sessile. The lamina is linear-lanceolate or slightly spathulate and up to 35 cm long and 6 cm wide. It has an acute apex and is gradually attenuate towards the base. Four to six longitudinal veins are present on either side of the midrib. Pinnate veins run obliquely towards the margin and are indistinct in the outer part of the lamina. 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 6 mm in diameter and may or may not have a curl.
Rosette and lower pitchers are ovate or narrowly ovate in the lower half and cylindrical above. They can be very large, reaching 35 cm in height. Terrestrial pitchers usually lack fringed wings, having a pair of ribs instead. The insertion of the pitcher mouth is slightly oblique. The flattened 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...
bears ribs spaced 0.5 to 1 mm apart. Its inner margin is lined with small teeth up to 1 mm long. It is not elongated into a neck. The inner surface of the pitcher is glandular in its lower half. Digestive glands are present at a density of 150 to 1500 per square centimetre. The pitcher lid is orbiculate to broad cordate, bears a distinct midline, and may be up to 8 cm long. Numerous large glands are present on the underside of the lid, concentrated near the two main lateral veins. An unbranched filiform 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...
(≤5 mm long) is inserted near the base of the lid.
Upper pitchers gradually arise from the ends of the tendrils, forming a 5 to 35 mm wide curve. They are infundibulate in the lower part and cylindrical above. They are up to 30 cm high and 8 cm wide. They may have very short wings (≤3 cm long) below the peristome. The pitcher mouth is oblique and acute or acuminate towards the lid. The expanded peristome is up to 35 mm wide and bears ribs spaced 0.5 to 1 mm apart. Its inner margin is lined with teeth which are about as long as they are wide. The inner surface of the pitcher is almost wholly glandular. The very small, overarched digestive glands occur at a density of 400 to 3000 per square centimetre. The pitcher lid is orbicular-ovate and up to 7.5 cm long. It bears a distinct midline and two distinct lateral veins. A number of large suborbicular glands are concentrated around these veins. A filiform spur (≤5 mm long) is inserted near the base of the lid.
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...
. 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 up to 18 cm long and 7 mm in diameter. The 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...
is attenuate, angular in cross section, and up to 46 cm long. 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 two-flowered 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. They may be up to 22 mm long. The oblong tepal
Tepal
Tepals are elements of the perianth, or outer part of a flower, which include the petals or sepals. The term tepal is more often applied specifically when all segments of the perianth are of similar shape and color, or undifferentiated, which is called perigone...
s are approximately 4 mm long. Stamen
Stamen
The stamen is the pollen producing reproductive organ of a flower...
s are around 5 mm long including the anthers.
Most parts of the plant are virtually glabrous. Developing pitchers have a sparse 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...
of short stellate hairs. Developing inflorescences are very densely hairy, becoming less hairy when mature. Pedicels and tepals are densely and shortly hairy. Stamens are more densely hairy near the base than near the anthers.
The stem and lamina are green. Lower pitchers are usually dark green with red blotches concentrated near the peristome, which is dark reddish-brown. Upper pitchers are yellowish-green with fewer blotches. Herbarium specimens are greenish or yellowish to light brown in colour. Faint red spots are visible on the outside surface of preserved pitchers. In dried specimens, the non-glandular portion of the inner surface is bluish and pruinose and may or may not be spotted.
Ecology
Western New Guinea
West Papua informally refers to the Indonesian western half of the island of New Guinea and other smaller islands to its west. The region is officially administered as two provinces: Papua and West Papua. The eastern half of New Guinea is Papua New Guinea.The population of approximately 3 million...
and a number of nearby islands in Cenderawasih Bay
Cenderawasih Bay
Cenderawasih Bay , also Teluk Sarera , formerly Geelvink Bay is a large bay in northern Province of Papua and West Papua, New Guinea, Indonesia, at . The Dutch name comes after a Dutch ship and family called Geelvinck...
. It has an altitudinal distribution of 0–850 m above sea level. In the southern part of the Lake Plains region of New Guinea it has been recorded from elevations of between 115 and 800 m. A smaller form of this species is also found near sea-level on the island of Biak
Biak
Biak features a tropical rainforest climate with nearly identical temperatures throughout the course of the year. The average annual temperature in the city is 27 degrees celsius, which is also generally the average temperature of each day in Biak...
.
Nepenthes insignis occurs in dense forest and on foothills. Plants usually grow epiphytically
Epiphyte
An epiphyte is a plant that grows upon another plant non-parasitically or sometimes upon some other object , derives its moisture and nutrients from the air and rain and sometimes from debris accumulating around it, and is found in the temperate zone and in the...
in thick layers of moss, especially in trees overhanging rivers. At higher altitudes, the species has also been recorded from sediment bars along rivers. Relative humidity
Relative humidity
Relative humidity is a term used to describe the amount of water vapor in a mixture of air and water vapor. It is defined as the partial pressure of water vapor in the air-water mixture, given as a percentage of the saturated vapor pressure under those conditions...
is always high in these habitats; the seeds of one plant which grew near a small waterfall were found to have germinated
Germination
Germination is the process in which a plant or fungus emerges from a seed or spore, respectively, and begins growth. The most common example of germination is the sprouting of a seedling from a seed of an angiosperm or gymnosperm. However the growth of a sporeling from a spore, for example the...
while still in their capsules.
In its natural habitat, N. insignis occurs sympatrically with N. ampullaria
Nepenthes ampullaria
Nepenthes ampullaria , the Flask-Shaped Pitcher-Plant, is a very distinctive and widespread species of Nepenthes, present in Borneo, Sumatra, Thailand, Peninsular Malaysia, Singapore, the Maluku Islands, and New Guinea...
, N. maxima
Nepenthes maxima
Nepenthes maxima , the Great Pitcher-Plant, is a carnivorous pitcher plant species of the genus Nepenthes. It has a relatively wide distribution covering Sulawesi, New Guinea, and the Maluku Islands. It is closely related to N. eymae....
(above 400 m altitude), N. mirabilis
Nepenthes mirabilis
Nepenthes mirabilis , or the Common Swamp Pitcher-Plant, is a tropical carnivorous plant species of the pitfall trap variety. It has by far the widest distribution of any Nepenthes species and is known from the following countries and regions: Borneo, Sumatra, Thailand, Peninsular Malaysia,...
, and plants tentatively identified as N. papuana
Nepenthes papuana
Nepenthes papuana is a tropical pitcher plant endemic to New Guinea. The specific epithet papuana is derived from Papua, an alternative name for the island.-Botanical history:...
that grow at 575 m altitude. One natural hybrid with N. mirabilis has been recorded.
Nepenthes insignis 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...
.
Carnivory
The prey of N. insignis appears to consist almost solely of big-winged cockroachCockroach
Cockroaches are insects of the order Blattaria or Blattodea, of which about 30 species out of 4,500 total are associated with human habitations...
es. It has been suggested that these nocturnal insects are attracted by odour produced by the plant.
Nepenthes insignis has been used in a study concerning the carnivory of Nepenthes and their production of the allelochemical plumbagin
Plumbagin
Plumbagin or 5-hydroxy-2-methyl-1,4-naphthoquinone is an organic compound with the chemical formula . It is regarded as a toxin.Plumbagin is a yellow dye, formally derived from naphthoquinone....
. It was shown that L-alanine
Alanine
Alanine is an α-amino acid with the chemical formula CH3CHCOOH. The L-isomer is one of the 20 amino acids encoded by the genetic code. Its codons are GCU, GCC, GCA, and GCG. It is classified as a nonpolar amino acid...
fed 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...
to the pitchers of N. insignis is used to build up plumbagin, but is not incorporated into rossoliside and plumbaside A. The results suggest that these compounds are used for storage and have very low turnover rates.
Related species
B. H. DanserB. H. Danser
Benedictus Hubertus Danser , often abbreviated B. H. Danser, was a Dutch taxonomist and botanist...
suggested that N. insignis is related to N. merrilliana
Nepenthes merrilliana
Nepenthes merrilliana is a tropical pitcher plant endemic to the Philippines. It produces some of the largest pitchers in the genus, rivalling those of N. rajah....
from the Philippines
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
. He placed both species in the Insignes
Nepenthes classification
The taxonomy of Nepenthes has been revised several times during the nineteenth and twentieth centuries.-Nineteenth century:The first subgeneric division of the Nepenthes was made by Joseph Dalton Hooker in his 1873 monograph, "Nepenthaceae"...
clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
, the members of which are characterised by coarse stems, large leaves, sparse indumentums, sessile leaves, and lids without appendages.
Nepenthes insignis has also been compared to N. sibuyanensis
Nepenthes sibuyanensis
Nepenthes sibuyanensis is a tropical pitcher plant endemic to Sibuyan Island in the Philippines, after which it is named.-Botanical history:...
, another Philippine endemic. It can be distinguished from that species on the basis of a number of morphological features. The former produces two-flowered 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....
, whereas those of N. sibuyanensis are one-flowered. The pitcher mouth of N. insignis is oblique, compared to almost horizontal in the latter. In addition, the peristome of N. sibuyanensis forms a short neck, while N. insignis lacks a neck completely. Furthermore, N. insignis has shorter peristome teeth than N. sibuyanensis (1 mm versus 5 mm). The pitchers of N. sibuyanensis also differ in shape, being ovate or slightly infundibulate.
Natural hybrids
A putative hybrid between N. insignis and N. mirabilisNepenthes mirabilis
Nepenthes mirabilis , or the Common Swamp Pitcher-Plant, is a tropical carnivorous plant species of the pitfall trap variety. It has by far the widest distribution of any Nepenthes species and is known from the following countries and regions: Borneo, Sumatra, Thailand, Peninsular Malaysia,...
was found by members of the 1994 field trip to New Guinea. The plant was growing at an altitude of around 500 m.
In Papua, N. insignis is commonly sympatric with N. ampullaria
Nepenthes ampullaria
Nepenthes ampullaria , the Flask-Shaped Pitcher-Plant, is a very distinctive and widespread species of Nepenthes, present in Borneo, Sumatra, Thailand, Peninsular Malaysia, Singapore, the Maluku Islands, and New Guinea...
and N. maxima
Nepenthes maxima
Nepenthes maxima , the Great Pitcher-Plant, is a carnivorous pitcher plant species of the genus Nepenthes. It has a relatively wide distribution covering Sulawesi, New Guinea, and the Maluku Islands. It is closely related to N. eymae....
, and hybrids involving these species may also occur, although none have been recorded to date.