Nepenthes aristolochioides
Encyclopedia
Nepenthes aristolochioides is a tropical pitcher plant
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 Sumatra
Sumatra
Sumatra is an island in western Indonesia, westernmost of the Sunda Islands. It is the largest island entirely in Indonesia , and the sixth largest island in the world at 473,481 km2 with a population of 50,365,538...

, where it grows at elevations of 1800–2500 m above sea level. It has an extremely unusual pitcher morphology, having an almost vertical opening to its traps.

The specific epithet aristolochioides is formed from the genus name Aristolochia
Aristolochia
Aristolochia is a large plant genus with over 500 species. Collectively known as birthworts, pipevines or Dutchman's pipes, they are the namesake of the family . They are widespread and occur in the most diverse climates. Some species, like A. utriformis and A...

and the 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...

 ending -oides, meaning "resembling". It refers to the similarity that the pitchers of this species bear, in both shape and pigmentation, to the specialised flowers of Aristolochia.

Botanical history

Nepenthes aristolochioides was first collected by Willem Meijer
Willem Meijer
Willem 'Wim' Meijer was a Dutch botanist and plant collector.-Background and education:Meijer was born in 1923 in The Hague, Netherlands. He received his Ph.D. from the University of Amsterdam in 1951...

 on August 5, 1956. 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...

, Meijer 6542, was collected on that date from Mount Tujuh
Mount Tujuh
Mount Tujuh is a caldera volcano in the Barisan Mountains of Sumatra. It has seven peaks, of which only three have been climbed. Mount Tujuh has a large caldera lake at its centre, Lake Gunung Tujuh. It is located within Kerinci Seblat National Park....

 (Tudjuh) in Jambi at an elevation of 2000 m. It is deposited 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...

 (L) in Leiden, but is in relatively poor condition. An isotype
Isotype
Isotype can refer to:* In crystallography, an "isotype" is a synonym for isomorph* In biology, per the International Code of Botanical Nomenclature, the "isotype" is a duplicate of the holotype....

 is held at Herbarium Bogoriense (BO), the herbarium of 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...

.

Although labelled as "new species?", the specimen was largely overlooked for over 30 years. In 1988, botanist Joachim Nerz
Joachim Nerz
Dr. Joachim Nerz is a taxonomist and botanist specialising in the carnivorous plant genera Heliamphora and Nepenthes. Nerz has described several new species, mostly with Andreas Wistuba.-Publications:...

 became aware of it upon visiting the herbarium of Leiden University
Leiden University
Leiden University , located in the city of Leiden, is the oldest university in the Netherlands. The university was founded in 1575 by William, Prince of Orange, leader of the Dutch Revolt in the Eighty Years' War. The royal Dutch House of Orange-Nassau and Leiden University still have a close...

. The name N. aristolochioides was coined quite early on; it was already being used in 1994 to informally refer to this (at the time undescribed
Undescribed taxon
In taxonomy, an undescribed taxon is a taxon that has been discovered, but not yet formally described and named. The various Nomenclature Codes specify the requirements for a new taxon to be validly described and named. Until such a description has been published, the taxon has no formal or...

) 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...

. That same year, taxonomist Jan Schlauer questioned the supposed lateral pitcher mouth of N. aristolochioides in email correspondence with botanist Matthew Jebb
Matthew Jebb
Dr. Matthew H. P. Jebb is an Irish taxonomist and botanist specialising in the ant plant genera Squamellaria, Myrmecodia, Hydnophytum, Myrmephytum and Anthorrhiza, as well as the carnivorous plant genus Nepenthes....

, who was preparing a revision of the genus at the time. Schlauer wrote that he had examined a specimen of this species (Meijer 7426) and that the seemingly vertical insertion of the pitcher mouth might be a result of the preservation process, whereby the traps had become "compressed along their longitudinal axes". In the summer of 1996, Nerz met with Schlauer and Meijer in the Frankfurt
Frankfurt
Frankfurt am Main , commonly known simply as Frankfurt, is the largest city in the German state of Hesse and the fifth-largest city in Germany, with a 2010 population of 688,249. The urban area had an estimated population of 2,300,000 in 2010...

 Palmengarten
Palmengarten
The Palmengarten is one of two botanical gardens in Frankfurt am Main, Hesse, Germany, and is located in the city district Westend-Nord. It is the largest garden of its kind in Germany....

, where Meijer showed him a photograph of the mysterious species. Together with Katrin Hinderhofer, Nerz organised a field trip to Sumatra in June 1996 and was successful in rediscovering N. aristolochioides in the wild.

Nepenthes aristolochioides was finally described by Matthew Jebb
Matthew Jebb
Dr. Matthew H. P. Jebb is an Irish taxonomist and botanist specialising in the ant plant genera Squamellaria, Myrmecodia, Hydnophytum, Myrmephytum and Anthorrhiza, as well as the carnivorous plant genus Nepenthes....

 and Martin Cheek
Martin Cheek
Dr. Martin Roy Cheek is a taxonomist and botanist specialising in the carnivorous plant genus Nepenthes.-Research:Cheek has described several new Nepenthes species, mostly with Matthew Jebb, including: N. argentii, N. aristolochioides, N. danseri, N. diatas,...

 in their monograph, "A skeletal revision of Nepenthes (Nepenthaceae)
A skeletal revision of Nepenthes (Nepenthaceae)
"A skeletal revision of Nepenthes " is a monograph by Matthew Jebb and Martin Cheek on the tropical pitcher plants of the genus Nepenthes. It was published in the May 1997 issue of the botanical journal Blumea. The work represented the first revision of the entire genus since John Muirhead...

", published in the May 1997 issue of the botanical journal Blumea
Blumea (journal)
Blumea - Journal of Plant Taxonomy and Plant Geography is a peer-reviewed journal of botany published by the National Herbarium of the Netherlands.Except for a short period during World War II, Blumea has been published continuously since 1934...

. Joachim Nerz
Joachim Nerz
Dr. Joachim Nerz is a taxonomist and botanist specialising in the carnivorous plant genera Heliamphora and Nepenthes. Nerz has described several new species, mostly with Andreas Wistuba.-Publications:...

 wrote a detailed description of the species for an issue of 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:...

published the following year. The next major treatments of the species appeared in Cheek and Jebb's updated 2001 work, "Nepenthaceae
Nepenthaceae (2001 monograph)
"Nepenthaceae" is a monograph by Martin Cheek and Matthew Jebb on the tropical pitcher plants of Malesia, which encompasses Brunei, Indonesia, Malaysia, Papua New Guinea, the Philippines, and Singapore. It was published in 2001 by the National Herbarium of the Netherlands as the fifteenth volume of...

"; Charles Clarke
Charles Clarke
Charles Rodway Clarke is a British Labour Party politician, who was the Member of Parliament for Norwich South from 1997 until 2010, and served as Home Secretary from December 2004 until May 2006.-Early life:...

's Nepenthes of Sumatra and Peninsular Malaysia
Nepenthes of Sumatra and Peninsular Malaysia
Nepenthes of Sumatra and Peninsular Malaysia is a monograph by Charles Clarke on the tropical pitcher plants of Sumatra, Peninsular Malaysia, and their minor surrounding islands. It was published in 2001 by Natural History Publications...

, also published in 2001; and Stewart McPherson
Stewart McPherson (geographer)
Stewart R. McPherson is a British geographer.He studied at the University of Durham in England, the University of Tübingen in Germany and Yale University in the United States....

's two-volume Pitcher Plants of the Old World
Pitcher Plants of the Old World
Pitcher Plants of the Old World is a two-volume monograph by Stewart McPherson on the pitcher plants of the genera Nepenthes and Cephalotus. It was published in May 2009 by Redfern Natural History Productions...

, released in 2009, which included colour photographs of specimens from a newly discovered locality.

Description

Nepenthes aristolochioides is a climbing plant. The stem, which may be branched, is terete and grows to 8 m in length and 5 mm in diameter. Internode
Plant 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 to obtusely angular in cross section and up to 15 cm long. Axillary bud
Axillary bud
The axillary bud is an embryonic shoot which lies at the junction of the stem and petiole of a plant.As the apical meristem grows and forms leaves, a region of meristematic cells are left behind at the node between the stem and the leaf. These axillary buds are usually dormant, inibited by auxin...

s are notably conspicuous in this species and are located 1.5–7 mm above the leaf axils.

Leaves are coriaceous and sessile. The lamina is linear, lanceolate or spathulate-lanceolate in form and up to 20 cm long by 5 cm wide. It has an acute or obtuse apex that may rarely be sub-peltate. It is gradually attenuate towards the base, becoming partly amplexicaul (clasping the stem for one-third to half of its circumference) and, rarely, slightly decurrent. Leaves of short stems have rounded auricles
Auricle (botany)
In botany, an auricle is a small ear-like projection from the base of a leaf or petal....

, whereas those of climbing stems lack auricles. Two to five longitudinal veins are present on either side of the midrib. They arise from the leaf base and occasionally along the length of the midrib, and are restricted to the distal third to two-thirds of the lamina, where they run parallel to the laminar margin. These longitudinal veins are indistinct in dried specimens. Pinnate veins are irregularly reticulate and indistinct. They are few in number and arise obliquely to eventually curve towards the laminar apex. The lower laminar surface bears sessile glands. 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 reach 15 cm in length. Those bearing rosette pitchers are typically around twice as long as the laminae and do not have a curl.
Nepenthes aristolochioides is noted for exhibiting relatively little dimorphism between its lower and upper pitchers. Rosette and lower pitchers are only briefly produced on small rosettes before the plant begins to climb, or on offshoots
Offshoot (plant)
Offshoots are lateral shoots that are produced on the main stem of a plant. They may be known colloquially as "suckers". Also see basal shoot....

 from the climbing stem. They arise from the ends of the tendrils, forming a 3–5 mm wide curve. They are broadly infundibular in the lower two-thirds and globose above, forming a dome above the pitcher opening. They reach 7 cm in height and 3 cm in width. A pair of wings (≤9 mm wide) runs down the front of the pitcher, either covering the length of the trap's ventral surface or being restricted to the upper part only. These wings bear fringe elements up to 10 mm long. The pitcher mouth is orbicular to ovate and up to 1.5 cm in diameter. It has a horizontal, oblique or almost vertical insertion. The gland
Gland
A gland is an organ in an animal's body that synthesizes a substance for release of substances such as hormones or breast milk, often into the bloodstream or into cavities inside the body or its outer surface .- Types :...

ular region covers almost the entire inner surface of the pitcher, but is often absent from the uppermost parts of the pitcher dome. Digestive glands are overarched; the lower ones measure 0.2–0.3 mm in diameter and are present at a density of around 200/cm2, whereas the upper ones are smaller and present at a density of around 500/cm2. 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...

 is broad, incurved, and up to 20 mm wide. Its ribs are spaced up to 0.5 mm apart. Its inner margin is lined with small teeth that are curled at their apices and are 2–3 times as long as they are broad. The pitcher 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 orbicular-cordate or ovate, up to 1.5 cm wide, and bears no appendages. Large nectar glands are present on the lid's entire lower surface, particularly around the midline. Three prominent veins are usually present on either side of the lid's midline. A broad and flattened 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...

 (≤7 mm long) is inserted at the base of the lid. It has been variously described as either branched or unbranched (simple).
Upper pitchers gradually arise from the ends of the tendrils, forming a 10 mm wide curve. They are narrowly infundibular in the lower half and utriculate above, forming a pronounced dome above the pitcher orifice. The ventral face of the trap is often noticeably flattened. Aerial traps are larger than their terrestrial counterparts, reaching 15 cm in height and 8 cm in width. They typically bear ribs in place of wings, although these may not be apparent at all. The pitcher mouth is subapical, ovate to circular, and measures up to 4 cm in diameter. It is angled even more steeply than in lower pitchers and may be positioned almost vertically. The glandular region usually covers the basal two-thirds of the pitcher cup's inner surface, or the pitcher may be wholly glandular. Digestive glands are slightly overarched; those near the bottom are 0.3–0.4 mm in diameter and occur at a density of around 200/cm2, whereas the upper ones are 0.2–0.3 mm in diameter and occur at a density of around 250/cm2. The peristome, which is up to 20 mm wide, is expanded, incurved, and internally flattened, forming an "entrance corridor" similar to a lobster pot. It extends for up to 2 mm on its outer margin, which is rounded. There is often a gap of up to 5 mm between the two lobes of the peristome near the base of the lid. The peristome bears ribs up to 0.8 mm high and spaced up to 0.8 mm apart, which terminate in indistinct teeth that are 2–3 times as long as they are broad. Large nectaries are located between the ribs. The pitcher lid is orbicular to ovate and is often held roughly horizontally, at a right angle to the pitcher orifice. It has a rounded to emarginate apex and a slightly cordate base, and measures up to 4 cm in length by 3 cm in width. It has no appendages, but bears numerous nectar glands, which are scattered quite evenly across the entire lower surface of the lid. These nectaries are circular to shortly elliptic and thinly bordered, measuring around 0.3 mm in diameter. They become slightly larger and more densely packed around the midline. Their rims are visibly asymmetric and are highest near the apical end of the lid. Three to four prominent veins are present on either side of the lid's midline. The spur is broad and flattened, measuring up to 10 mm in length. It has 2–4 acute points at its apex, and has been variously described as either simple or branched.

Nepenthes aristolochioides 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...

 up to 30 cm long. Both 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...

 and 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...

 may be up to 15 cm long, although the latter is usually shorter in female plants. The peduncle is up to 4 mm in diameter. Pedicel
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....

s are simple-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...

eolate and one-flowered. The basalmost ones are up to 12 mm long, whereas those higher up the rachis reach only 6 mm. 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 ovate and up to 4 mm long. Fruit
Fruit
In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...

s are up to 20 mm long and 4 mm wide, and bear lanceolate valves. Seed
Seed
A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...

s are filiform.

Most parts of the plant are glabrous. Where present, the 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...

 is inconspicuous; hairs are found on the leaf axils, midribs, laminar margins, and parts of the pitchers (especially around the peristome and on the lid, and in developing pitchers). The indumentum is sparse and consists of short, simple or irregularly branching, appressed hairs, which are white to silver in colour and measure up to 0.2 mm and sometimes even 2 mm in length.

The stem, laminae, tendrils and midribs are yellowish-green. On their outer surfaces, pitchers are white to reddish with numerous reddish-brown to purple speckles, with both lower and upper pitchers exhibiting similar colouration. The dark blotches are often denser in the upper part of the pitcher. The peristome is usually dark red or purple, being particularly dark in rosette pitchers. The undersurface of the lid is dark red or purple throughout, while the upper surface is speckled like the rest of the pitcher. The inner surface of the pitcher is white to light yellow throughout. Herbarium specimens are brown to dark brown, the preserved pitchers having conspicuous dark spots.

Little variation has been observed within natural populations of N. aristolochioides and no infraspecific taxa have been described.

Ecology

Nepenthes aristolochioides is endemic to Sumatra
Sumatra
Sumatra is an island in western Indonesia, westernmost of the Sunda Islands. It is the largest island entirely in Indonesia , and the sixth largest island in the world at 473,481 km2 with a population of 50,365,538...

 and has an altitudinal distribution of 1800–2500 m above sea level. In 2001, 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...

 wrote that the species was only known from Mount Tujuh
Mount Tujuh
Mount Tujuh is a caldera volcano in the Barisan Mountains of Sumatra. It has seven peaks, of which only three have been climbed. Mount Tujuh has a large caldera lake at its centre, Lake Gunung Tujuh. It is located within Kerinci Seblat National Park....

 in Jambi, although specimens collected by Herbert Christopher Robinson
Herbert Christopher Robinson
Herbert Christopher Robinson was a British zoologist and ornithologist. He is principally known for conceiving and initiating the major ornithological reference The Birds of the Malay Peninsula....

 and Cecil Boden Kloss
Cecil Boden Kloss
Cecil Boden Kloss was an English zoologist. He was an expert on the mammals and birds of Southeast Asia.In the early 1900s Kloss accompanied the American naturalist William Louis Abbott in exploring the Andaman and Nicobar islands. From 1908 he worked under Herbert Christopher Robinson at the...

 labelled as being taken from "Mt. Kerinci" suggested that it may be more widespread in the region. Mount Kerinci
Mount Kerinci
Mount Kerinci is the highest volcano in Indonesia, and the highest peak on the island of Sumatra...

 is Sumatra's highest peak and neighbours Mount Tujuh. Clarke noted that since most of the mountain remains unexplored, there is a good chance that N. aristolochioides occurs there as well. The full range of N. aristolochioides on Mount Tujuh is also unknown, since only three of the mountain's seven peaks had been climbed as of 2001. In 2009, Stewart McPherson
Stewart McPherson (geographer)
Stewart R. McPherson is a British geographer.He studied at the University of Durham in England, the University of Tübingen in Germany and Yale University in the United States....

 reported that N. aristolochioides was known from three subpopulations in Kerinci Seblat National Park
Kerinci Seblat National Park
Kerinci Seblat National Park is the largest national park in Sumatra Indonesia. It has a total area of 13,791 km2, and spans four provinces: West Sumatra, Jambi, Bengkulu and South Sumatra....

. Of these, one (the type locality on Mount Tujuh) may already be extinct
Extinction
In biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...

 due to poaching by plant collectors; in 2007, E'En Endatno observed only a single N. aristolochioides plant on Mount Tujuh. The other two sites are located on remote peaks and support only "a few dozen" plants, as determined by McPherson.
Nepenthes aristolochioides inhabits Sphagnum
Sphagnum
Sphagnum is a genus of between 151 and 350 species of mosses commonly called peat moss, due to its prevalence in peat bogs and mires. A distinction is made between sphagnum moss, the live moss growing on top of a peat bog on one hand, and sphagnum peat moss or sphagnum peat on the other, the...

-dominated mossy forest near the tops of steep ridges. It usually grows terrestrially, but can also occur as an epiphyte
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 pockets of moss on tree trunks. The species occurs sympatrically
Sympatry
In biology, two species or populations are considered sympatric when they exist in the same geographic area and thus regularly encounter one another. An initially-interbreeding population that splits into two or more distinct species sharing a common range exemplifies sympatric speciation...

 with N. gymnamphora
Nepenthes gymnamphora
Nepenthes gymnamphora is a tropical pitcher plant native to the Indonesian islands of Java and Sumatra. There is much debate surrounding the taxonomic status of this species and the taxa N. pectinata and N. xiphioides....

and N. singalana
Nepenthes singalana
Nepenthes singalana is a highland Nepenthes pitcher plant species native to the island of Sumatra. It is most closely related to N. diatas and N. spathulata.-Taxonomy:...

. It grows with the former in montane forest and swamp
Swamp
A swamp is a wetland with some flooding of large areas of land by shallow bodies of water. A swamp generally has a large number of hammocks, or dry-land protrusions, covered by aquatic vegetation, or vegetation that tolerates periodical inundation. The two main types of swamp are "true" or swamp...

s dominated by Pandanus
Pandanus
Pandanus is a genus of monocots with about 600 known species. They are numerous palmlike dioecious trees and shrubs native of the Old World tropics and subtropics. They are classified in the order Pandanales, family Pandanaceae.-Overview:...

species that line the shoreline of a crater lake. The altitudinal distribution of N. gymnamphora on Mount Tujuh (1800–2100 m) overlaps that of N. aristolochioides, but no natural hybrids have been observed. A small form of N. singalana occurs in the same habitat as N. aristolochioides, but appears to occupy a different ecological niche
Ecological niche
In ecology, a niche is a term describing the relational position of a species or population in its ecosystem to each other; e.g. a dolphin could potentially be in another ecological niche from one that travels in a different pod if the members of these pods utilize significantly different food...

; it is generally confined to the forest floor while N. aristolochioides often climbs into the canopy. A number of plants representing the natural hybrid N. aristolochioides × N. singalana have been recorded.

Nepenthes aristolochioides is listed as Critically Endangered
Critically Endangered
Critically Endangered is the highest risk category assigned by the IUCN Red List for wild species. Critically Endangered means that a species' numbers have decreased, or will decrease, by 80% within three generations....

 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...

, as its known distribution was restricted to a single mountain at the time of the assessment. Despite the fact that all known populations of the species lie within Kerinci Seblat National Park
Kerinci Seblat National Park
Kerinci Seblat National Park is the largest national park in Sumatra Indonesia. It has a total area of 13,791 km2, and spans four provinces: West Sumatra, Jambi, Bengkulu and South Sumatra....

, it is severely threatened by over-collection, because its unique pitcher morphology makes it particularly sought-after. In 2010, the Rare Nepenthes Collection was established with the aim of conserving 4 of the most endangered Nepenthes species: N. aristolochioides, N. clipeata
Nepenthes clipeata
Nepenthes clipeata , or the Shield-Leaved Pitcher-Plant, is a tropical pitcher plant known only from the near-vertical granite cliff faces of Mount Kelam in Kalimantan, Borneo...

, N. khasiana
Nepenthes khasiana
Nepenthes khasiana |endemic]]) is a tropical pitcher plant of the genus Nepenthes. It is the only Nepenthes species native to India....

, and N. rigidifolia
Nepenthes rigidifolia
Nepenthes rigidifolia is a tropical pitcher plant endemic to Sumatra, where it grows at elevations of 1000–1600 m above sea level.The specific epithet rigidifolia is formed from the Latin words rigidus and folia . It refers to the stiff, coriaceous texture of the leaf blade...

.

Carnivory

Two different trapping mechanisms have been proposed for the lower and upper pitchers of N. aristolochioides.

The lower pitchers of this species frequently develop embedded in Sphagnum
Sphagnum
Sphagnum is a genus of between 151 and 350 species of mosses commonly called peat moss, due to its prevalence in peat bogs and mires. A distinction is made between sphagnum moss, the live moss growing on top of a peat bog on one hand, and sphagnum peat moss or sphagnum peat on the other, the...

moss, with only the top of the traps visible. Joachim Nerz
Joachim Nerz
Dr. Joachim Nerz is a taxonomist and botanist specialising in the carnivorous plant genera Heliamphora and Nepenthes. Nerz has described several new species, mostly with Andreas Wistuba.-Publications:...

 suggested that they act as simple pitfall traps specialised for trapping ground-dwelling insects. The insects crawl into the pitcher through the small mouth and fall to the bottom of the pitcher cup. Unable to climb out, they drown in the digestive fluid.
Along with N. klossii
Nepenthes klossii
Nepenthes klossii is a tropical pitcher plant endemic to New Guinea.-Botanical history:Nepenthes klossii was discovered in southwestern New Guinea during the Wollaston Expedition of 1912 to 1913...

, N. aristolochioides is the only species in the genus to employ domed pitchers with white patches that allow sunlight to illuminate the interior. When viewed from the front, the peristome and lid appear dark, in contrast to the inner surface of the pitcher, which is brightly lit by light passing through the top of the pitcher dome. It has been suggested that in upper pitchers this adaptation serves to attract flying insects in a similar manner to the North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

n pitcher plants Darlingtonia californica
Darlingtonia californica
Darlingtonia californica , also called the California Pitcher plant, Cobra Lily, or Cobra Plant, is a carnivorous plant, the sole member of the genus Darlingtonia in the family Sarraceniaceae. It is native to Northern California and Oregon, growing in bogs and seeps with cold running water...

, Sarracenia minor
Sarracenia minor
Sarracenia minor, also known as the Hooded pitcher plant, is a perennial, terrestrial, rhizomatous, herbaceous, carnivorous plant in the genus Sarracenia. Like all the Sarracenia, it is native to the New World.-Etymology:...

, and Sarracenia psittacina
Sarracenia psittacina
Sarracenia psittacina, also known as the parrot pitcher plant, is a carnivorous plant in the genus Sarracenia. Like all the Sarracenia, it is native to North America, in the Southeastern United States....

. A similar trapping mechanism has also been proposed for N. jacquelineae
Nepenthes jacquelineae
Nepenthes jacquelineae is a tropical pitcher plant endemic to Sumatra. Due to its unique pitcher morphology, it is considered to be one of the most spectacular Nepenthes species native to the island.-Botanical history:...

. This is supported by the fact that most of the prey caught by N. aristolochioides consists of small flies
Fly
True flies are insects of the order Diptera . They possess a pair of wings on the mesothorax and a pair of halteres, derived from the hind wings, on the metathorax...

, which are attracted to bright light sources. Prey are often disorientated inside the upper pitchers of N. aristolochioides. Unable to find the exit, they eventually fall into the pitcher fluid and drown. As such, the pitchers have features of lobster-pot traps.

Nepenthes aristolochioides produces extremely thick, mucilaginous
Mucilage
Mucilage is a thick, gluey substance produced by most plants and some microorganisms. It is a polar glycoprotein and an exopolysaccharide.It occurs in various parts of nearly all classes of plant, usually in relatively small percentages, and is frequently associated with other substances, such as...

 pitcher liquid, which coats the entire inner surfaces of the traps in a thin film. The pitchers of this species appear to function at least in part as flypaper traps, with the sticky inner walls trapping flying insects above the surface of the fluid. Similarly viscous pitcher fluid is also found in seven other closely allied Sumatra
Sumatra
Sumatra is an island in western Indonesia, westernmost of the Sunda Islands. It is the largest island entirely in Indonesia , and the sixth largest island in the world at 473,481 km2 with a population of 50,365,538...

n species: N. dubia
Nepenthes dubia
Nepenthes dubia is a tropical pitcher plant endemic to Sumatra. The specific epithet dubia is the Latin word for "doubtful".-Botanical history:...

, N. flava
Nepenthes flava
Nepenthes flava is a tropical pitcher plant endemic to northern Sumatra, where it grows in montane forest at 1800–2200 m above sea level....

, N. inermis
Nepenthes inermis
Nepenthes inermis is a tropical pitcher plant endemic to Sumatra. The specific epithet inermis is Latin for "unarmed" and probably refers to the upper pitchers of this species, which are unique in that they completely lack a peristome....

, N. jacquelineae
Nepenthes jacquelineae
Nepenthes jacquelineae is a tropical pitcher plant endemic to Sumatra. Due to its unique pitcher morphology, it is considered to be one of the most spectacular Nepenthes species native to the island.-Botanical history:...

, N. jamban
Nepenthes jamban
Nepenthes jamban is a tropical pitcher plant endemic to northern Sumatra. The specific epithet jamban is the Indonesian word for "toilet" and refers to the shape of the pitchers.-Botanical history:...

, N. talangensis
Nepenthes talangensis
Nepenthes talangensis is a tropical pitcher plant endemic to Sumatra, where it grows in upper montane forest at elevations of 1800–2500 m above sea level....

, and N. tenuis
Nepenthes tenuis
Nepenthes tenuis is a tropical pitcher plant endemic to Sumatra. The species was first collected in 1957, from a remote mountain in the western part of the island. It remained undescribed until 1994, and was only rediscovered in the wild in 2002. Prior to this, N...

. Together with N. aristolochioides, these species all share infundibular pitchers that are wholly glandular or almost so.

No infaunal organisms
Nepenthes infauna
Nepenthes infauna are the organisms that inhabit the pitchers of Nepenthes plants. These include fly and midge larvae, spiders, mites, ants, and even a species of crab, Geosesarma malayanum. The most common and conspicuous predators found in pitchers are mosquito larvae, which consume large...

 have been recorded from the pitchers of N. aristolochioides. This is not due to a lack of potential inhabitants; pitchers of N. singalana
Nepenthes singalana
Nepenthes singalana is a highland Nepenthes pitcher plant species native to the island of Sumatra. It is most closely related to N. diatas and N. spathulata.-Taxonomy:...

, which grow alongside N. aristolochioides, support large populations of such organisms. It is thought that the structure of the traps may serve to disorientate emerging adults and so infaunal species avoid colonising them.

Related species

The unusual pitcher morphology of N. aristolochioides makes it difficult to confuse with any other species; the almost vertical orientation of the pitcher mouth is a unique characteristic.

Joachim Nerz
Joachim Nerz
Dr. Joachim Nerz is a taxonomist and botanist specialising in the carnivorous plant genera Heliamphora and Nepenthes. Nerz has described several new species, mostly with Andreas Wistuba.-Publications:...

 noted that N. aristolochioides shows "close affinities" to N. talangensis
Nepenthes talangensis
Nepenthes talangensis is a tropical pitcher plant endemic to Sumatra, where it grows in upper montane forest at elevations of 1800–2500 m above sea level....

. However, it may be easily distinguished from that species on the basis of the pitcher mouth, which is horizontal in N. talangensis. In addition, the pitcher mouth of N. talangensis is elongated into a short neck, whereas N. aristolochioides lacks a neck altogether, with the lid being inserted in front of the pitcher. Both the mouth and lid are considerably larger in N. talangensis. The two 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...

 also differ somewhat in growth habit; N. talangensis occurs only terrestrially and is a weak climber, whereas N. aristolochioides occasionally grows as an epiphyte
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...

 and climbs high into the forest canopy.

The laminar morphology of N. aristolochioides is also similar to that of N. bongso
Nepenthes bongso
Nepenthes bongso is a tropical pitcher plant endemic to Sumatra, where it has an altitudinal distribution of 1000–2700 m above sea level. The specific epithet bongso refers to the Indonesian legend of Putri Bungsu , the spirit guardian of Mount Marapi.The species was formally described by Pieter...

, although N. aristolochioides is easily distinguished from this species by the shape of its pitchers and the hooded nectaries of the lid.

In 2001, 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...

 performed a cladistic analysis of the Nepenthes species of Sumatra and 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...

 using 70 morphological characteristics of each taxon. The following is part of the resultant cladogram
Cladogram
A cladogram is a diagram used in cladistics which shows ancestral relations between organisms, to represent the evolutionary tree of life. Although traditionally such cladograms were generated largely on the basis of morphological characters, DNA and RNA sequencing data and computational...

, showing "Clade 1", which has 51% bootstrap support. Its most strongly supported subclade is the sister pair of N. inermis and N. dubia, having 95% support.
Although N. aristolochioides resembles N. klossii
Nepenthes klossii
Nepenthes klossii is a tropical pitcher plant endemic to New Guinea.-Botanical history:Nepenthes klossii was discovered in southwestern New Guinea during the Wollaston Expedition of 1912 to 1913...

in some respects, the two species are geographically isolated from each other and are not thought to be closely related. The unique adaptations of these taxa might represent an example of convergent evolution
Convergent evolution
Convergent evolution describes the acquisition of the same biological trait in unrelated lineages.The wing is a classic example of convergent evolution in action. Although their last common ancestor did not have wings, both birds and bats do, and are capable of powered flight. The wings are...

, whereby two organisms that are not closely related independently acquire similar characteristics while evolving in separate, but comparable, ecosystems.

Natural hybrids

Only one natural hybrid involving N. aristolochioides is known. Nepenthes aristolochioides × N. singalana
Nepenthes singalana
Nepenthes singalana is a highland Nepenthes pitcher plant species native to the island of Sumatra. It is most closely related to N. diatas and N. spathulata.-Taxonomy:...

has been found in dense mossy forest on two ridges of Mount Tujuh
Mount Tujuh
Mount Tujuh is a caldera volcano in the Barisan Mountains of Sumatra. It has seven peaks, of which only three have been climbed. Mount Tujuh has a large caldera lake at its centre, Lake Gunung Tujuh. It is located within Kerinci Seblat National Park....

, only one of which is populated by N. aristolochioides. It is relatively rare, which suggests that the two species flower at different times of the year. This hybrid is smaller than either of its parent species; the pitchers rarely exceed 5 cm in height. The lower pitchers resemble those of N. talangensis
Nepenthes talangensis
Nepenthes talangensis is a tropical pitcher plant endemic to Sumatra, where it grows in upper montane forest at elevations of 1800–2500 m above sea level....

, but differ in having more pronounced peristome teeth. Upper pitchers are infundibular in the lower parts, ovoid in the middle, and cylindrical in the upper parts. This hybrid can be distinguished from N. aristolochioides on the basis of its narrow, cylindrical peristome and oblique mouth, as opposed to almost vertical in the latter.

External links

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