Nepenthes pilosa
Encyclopedia
Nepenthes pilosa is a tropical pitcher plant
endemic to Borneo
. It is characterised by a dense indumentum
of long yellow-brown hairs. Pitchers have a distinctive hook-shaped appendage on the underside of the lid. The specific epithet derives from the Latin
word pilosus, meaning "hairy".
Nepenthes pilosa was for a long time conflated with N. chaniana
and, with the exception of the type material, all specimens identified as N. pilosa prior to the description of N. chaniana in 2006 actually represent the latter species.
In Pitcher-Plants of Borneo
, Anthea Phillipps
and Anthony Lamb
list this species under the common name
Golden-Furred Pitcher-Plant, although this was published before the recognition of N. chaniana as a distinct species.
nese plant collector Amdjah during the Nieuwenhuis Expedition, on which Amdjah also made the first collection of N. ephippiata
.
Nepenthes pilosa was formally described
in 1928 by Dutch
botanist B. H. Danser
in his seminal monograph "The Nepenthaceae of the Netherlands Indies
". Danser designated Amdjah 491 as the type specimen and also referred Amdjah 499 to the species. Both specimens were colleced on January 28, 1899, from Bukit Batu Lesung, a mountain located near the center of Kalimantan
, at an altitude of approximately 1600 m. Danser also listed a "very doubtful" male specimen (Mjöberg 46) under his description of N. pilosa. This specimen was collected by Eric Mjöberg
between October and December 1925, from Bukit Batu Tiban at an altitude of 1700 m. Danser wrote of Mjöberg 46:
All three specimens mentioned by Danser are deposited at Herbarium Bogoriense (BO), the herbarium
of the Bogor Botanical Gardens
.
In his 1997 monograph, Nepenthes of Borneo
, botanist Charles Clarke
noted that several authors had noticed discrepancies between the type material of N. pilosa and plants identified as this species in the field:
Despite this, Matthew Jebb
and Martin Cheek
did not distinguish the East Malaysia
n plants from N. pilosa in their monograph published the same year. Similarly, in Pitcher-Plants of Borneo
(1996), Anthea Phillipps
and Anthony Lamb
treated plants from Mount Alab, Crocker Range
, as N. pilosa, following the interpretation of J. R. Turnbull and A. T. Middleton in an unpublished mimeograph report from 1981.
Although he treated plants from East Malaysia
as N. pilosa in his 1997 monograph, Charles Clarke doubted their conspecificity
. He visited the type locality of N. pilosa in 2004, making the first collection of this species since 1899. In July 2006, Clarke revisited wild populations of N. pilosa on Bukit Batu Lesung to confirm its status as a distinct species. Later that year he, together with Ch'ien Lee
and Stewart McPherson
, published the formal description of N. chaniana
. This revised circumscription means that N. pilosa is endemic to Kalimantan
, while N. chaniana is native to Sabah
and Sarawak
. As such, virtually all plants in cultivation up to that time under the name N. pilosa actually represented N. chaniana
.
s are up to 7 cm long and circular in cross section.
Leaves are petiolate and coriaceous or thin-coriaceous in texture. The lamina or leaf blade is obovate-lanceolate to lanceolate in shape. It measure up to 30 cm in length by 7.5 cm in width. The apex of the lamina is rounded or shortly acuminate and may be slightly peltate. The lamina is abruptly attenuate towards the base. The petiole
is triangular and up to 6 mm wide. It is grooved and bears a pair of narrow wings that form an amplexicaul sheath around the stem and are decurrent for up to 2.5 cm, terminating abruptly in a rounded base. Four or five logitudinal veins are present on either side of the midrib. Pinnate veins are indistinct and irregularly reticulate. Tendril
s are usually around 1.5 to 2 times as long as the lamina.
Rosette and lower pitchers are ovate in the lower portion, becoming cylindrical above. They are up to 10 cm high by 4 cm wide and typically have prominent ribs on their ventral surface in place of wings. The pitcher mouth has an oblique insertion. The peristome
is flattened and up to 7 mm wide at the rear. It bears a series of ribs spaced ⅓ to ¼ mm apart, which terminate in short teeth that are barely longer than they are broad. The gland
ular region covers the ventricose portion of the pitcher's inner surface. The digestive glands are overarched and number 600 to 700 per square centimetre. The pitcher lid or operculum
is roughly orbicular, subcordate, and around 2.5 cm long by 2.5 cm wide. It is relatively flat, although it has a central keel in its basal part. Extrafloral nectaries are scattered on the underside of the lid, becoming smaller and more numerous towards the margins.
Upper pitchers gradually arise from the ends of the tendrils, forming a 15 to 20 mm wide curve. They are infundibular in shape and reach much greater dimensions than their lower counterparts, measuring up to 18 cm high by 8 cm wide. Like terrestrial pitchers, they lack wings, instead having a pair of prominent ribs. The pitcher mouth is positioned almost horizontally at the front, but rises into a neck (≤3 cm high) towards the rear. The flattened peristome is up to 12 mm wide and bears ribs spaced ⅓ mm apart which terminate in short teeth. Virtually the entire inner surface of the pitcher is glandular, having very small overarched glands at a density of 2000 to 2500 per square centimetre. The pitcher lid suborbicular, deeply cordate, and measures up to 7 cm in length. Small round glands are scattered throughout the lower surface of the lid and a prominent hook-like crest is present near the base.
Nepenthes pilosa has a conspicuous indumentum
of yellow-brown hairs. This covering is particularly dense on developing parts and on the underside of the lamina in mature leaves. It is notably absent from the upper surface of the lamina.
Herbarium specimens dry to a reddish-brown colour on the stem and the underside of the leaves, while the upper surface of the lamina is typically fallow
.
of Bukit Batu Lesung (likely synonymous with Ketang Lesung) in East Kalimantan
, Borneo
. The mountain has been described as a "long sandstone
ridge with several small peaks". The typical habitat of this species is mossy forest. A population of approximately 200 plants has been found growing at an elevation of around 1600 or 1700 m.
Nepenthes pilosa is classified as Endangered
on the 2006 IUCN Red List of Threatened Species
, based on an assessment carried out in 2000.
and N. chaniana
.
B. H. Danser
suggested that N. pilosa is most closely related to N. burbidgeae and, prior to the rediscovery of wild populations of N. pilosa, the species was considered a possible heterotypic synonym of N. burbidgeae by some authors. N. pilosa differs in having a more prominent and extensive indumentum
.
Compared to N. chaniana, the pitchers of N. pilosa are more cylindrical, squater, and not as laterally-compressed.
Nepenthes glandulifera
has a similarly extensive indumentum, but lacks a well-developed lid appendage and bears many prominent extrafloral nectaries.
and N. veitchii
, but the latter is now known to involve N. chaniana
instead of N. pilosa, while the former is thought to represent the cross N. fusca
× N. lowii.
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 is characterised by a dense 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 long yellow-brown hairs. Pitchers have a distinctive hook-shaped appendage on the underside of the lid. The specific epithet derives from 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...
word pilosus, meaning "hairy".
Nepenthes pilosa was for a long time conflated with N. chaniana
Nepenthes chaniana
Nepenthes chaniana ]]) is a highland pitcher plant species belonging to the genus Nepenthes. It is characterised by a dense indumentum of long, white hairs. Pitchers are cylindrical and mostly white to yellow in colouration....
and, with the exception of the type material, all specimens identified as N. pilosa prior to the description of N. chaniana in 2006 actually represent the latter species.
In Pitcher-Plants of Borneo
Pitcher-Plants of Borneo
Pitcher-Plants of Borneo is a monograph by Anthea Phillipps and Anthony Lamb on the tropical pitcher plants of Borneo. It was first published in 1996 by Natural History Publications , in association with the Royal Botanic Gardens, Kew and the Malaysian Nature Society...
, Anthea Phillipps
Anthea Phillipps
Anthea Phillipps B.Sc. is a British botanist. Phillipps was brought up in Sabah, Borneo as a child . She received a Botany degree from the University of Durham, England. She worked at the Sabah Museum before joining the Sabah Parks service from 1980 to 1987 as Park Ecologist, where she studied...
and Anthony Lamb
Anthony Lamb
Anthony L. Lamb M.A., Dip. Ag., D.T.A. is a British botanist, born in Sri Lanka, and specialising in the flora of Borneo. Lamb was educated at Blundell's School in Tiverton and at St John's College at Cambridge...
list this species under the common name
Common name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...
Golden-Furred Pitcher-Plant, although this was published before the recognition of N. chaniana as a distinct species.
Botanical history
Nepenthes pilosa was discovered in 1899 by JavaJava
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...
nese plant collector Amdjah during the Nieuwenhuis Expedition, on which Amdjah also made the first collection of N. ephippiata
Nepenthes ephippiata
Nepenthes ephippiata , or the Saddle-Leaved Pitcher-Plant, is a tropical pitcher plant endemic to Borneo. It occurs in the Hose Mountains of central Sarawak, as well as Mount Raya and Bukit Lesung in Kalimantan. Plants from the Hose Mountains appear to lack the decurrent leaf attachment found in...
.
Nepenthes pilosa was 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...
in 1928 by Dutch
Netherlands
The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...
botanist B. H. Danser
B. H. Danser
Benedictus Hubertus Danser , often abbreviated B. H. Danser, was a Dutch taxonomist and botanist...
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...
". Danser designated Amdjah 491 as the type specimen and also referred Amdjah 499 to the species. Both specimens were colleced on January 28, 1899, from Bukit Batu Lesung, a mountain located near the center of Kalimantan
Kalimantan
In English, the term Kalimantan refers to the Indonesian portion of the island of Borneo, while in Indonesian, the term "Kalimantan" refers to the whole island of Borneo....
, at an altitude of approximately 1600 m. Danser also listed a "very doubtful" male specimen (Mjöberg 46) under his description of N. pilosa. This specimen was collected by Eric Mjöberg
Eric Mjöberg
Dr Eric Georg Mjöberg was a Swedish zoologist and ethnographer who led the first Swedish scientific expeditions to Australia in the early 1900s, and worked in Indonesia. The plant Vaccinium mjoebergii J.J.Sm...
between October and December 1925, from Bukit Batu Tiban at an altitude of 1700 m. Danser wrote of Mjöberg 46:
"It is only one leaf with upper pitcher, and an inflorescence not certainly belonging to the same plant; the pitcher is not congruent with that of number Amdjah 491 and this is the reason I have not completed the description with that of the male inflorescence."
All three specimens mentioned by Danser are deposited at Herbarium Bogoriense (BO), the herbarium
Herbarium
In botany, a herbarium – sometimes known by the Anglicized term herbar – is a collection of preserved plant specimens. These specimens may be whole plants or plant parts: these will usually be in a dried form, mounted on a sheet, but depending upon the material may also be kept in...
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...
.
In his 1997 monograph, Nepenthes of Borneo
Nepenthes of Borneo
Nepenthes of Borneo is a monograph by Charles Clarke on the tropical pitcher plants of Borneo. It was first published in 1997 by Natural History Publications , and reprinted in 2006. Clarke describes it as "primarily an ecological monograph"...
, botanist 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...
noted that several authors had noticed discrepancies between the type material of N. pilosa and plants identified as this species in the field:
"[T]he illustration of the type of N. pilosa in Danser (1928) does not correspond very well with plants identified as N. pilosa in East Malaysia (J. Schlauer, pers. comm.). M. Jebb (pers. comm.) also notes that the upper pitcher on the type is unusual [...]"
Despite this, 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,...
did not distinguish the East Malaysia
East Malaysia
East Malaysia, also known as Malaysian Borneo, is the part of Malaysia located on the island of Borneo. It consists of the Malaysian states of Sabah and Sarawak, and the Federal Territory of Labuan. It lies to the east from Peninsular Malaysia , which is located on the Malay Peninsula. The two are...
n plants from N. pilosa in their monograph published the same year. Similarly, in Pitcher-Plants of Borneo
Pitcher-Plants of Borneo
Pitcher-Plants of Borneo is a monograph by Anthea Phillipps and Anthony Lamb on the tropical pitcher plants of Borneo. It was first published in 1996 by Natural History Publications , in association with the Royal Botanic Gardens, Kew and the Malaysian Nature Society...
(1996), Anthea Phillipps
Anthea Phillipps
Anthea Phillipps B.Sc. is a British botanist. Phillipps was brought up in Sabah, Borneo as a child . She received a Botany degree from the University of Durham, England. She worked at the Sabah Museum before joining the Sabah Parks service from 1980 to 1987 as Park Ecologist, where she studied...
and Anthony Lamb
Anthony Lamb
Anthony L. Lamb M.A., Dip. Ag., D.T.A. is a British botanist, born in Sri Lanka, and specialising in the flora of Borneo. Lamb was educated at Blundell's School in Tiverton and at St John's College at Cambridge...
treated plants from Mount Alab, Crocker Range
Crocker Range
Crocker Range , is a mountain range on the island of Borneo. Politically, it is within the boundary of the Malaysian state of Sabah, located in the northern half of Borneo. The mountain range separates the east coast and west coast of Sabah. At an average height of 1800m, it is the highest mountain...
, as N. pilosa, following the interpretation of J. R. Turnbull and A. T. Middleton in an unpublished mimeograph report from 1981.
Although he treated plants from East Malaysia
East Malaysia
East Malaysia, also known as Malaysian Borneo, is the part of Malaysia located on the island of Borneo. It consists of the Malaysian states of Sabah and Sarawak, and the Federal Territory of Labuan. It lies to the east from Peninsular Malaysia , which is located on the Malay Peninsula. The two are...
as N. pilosa in his 1997 monograph, Charles Clarke doubted their conspecificity
Conspecificity
Conspecificity is a concept in biology. Two or more individual organisms, populations, or taxa are conspecific if they belong to the same species....
. He visited the type locality of N. pilosa in 2004, making the first collection of this species since 1899. In July 2006, Clarke revisited wild populations of N. pilosa on Bukit Batu Lesung to confirm its status as a distinct species. Later that year he, together with Ch'ien Lee
Ch'ien Lee
Ch'ien C. Lee is a photographer and botanist specialising in the carnivorous plant genus Nepenthes. Lee has described several new Nepenthes species, including N. chaniana, N. gantungensis, N. glandulifera, N. jamban, N. lingulata, N. palawanensis, N. pitopangii,...
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....
, published the formal description of N. chaniana
Nepenthes chaniana
Nepenthes chaniana ]]) is a highland pitcher plant species belonging to the genus Nepenthes. It is characterised by a dense indumentum of long, white hairs. Pitchers are cylindrical and mostly white to yellow in colouration....
. This revised circumscription means that N. pilosa is endemic to Kalimantan
Kalimantan
In English, the term Kalimantan refers to the Indonesian portion of the island of Borneo, while in Indonesian, the term "Kalimantan" refers to the whole island of Borneo....
, while N. chaniana is native to Sabah
Sabah
Sabah is one of 13 member states of Malaysia. It is located on the northern portion of the island of Borneo. It is the second largest state in the country after Sarawak, which it borders on its southwest. It also shares a border with the province of East Kalimantan of Indonesia in the south...
and Sarawak
Sarawak
Sarawak is one of two Malaysian states on the island of Borneo. Known as Bumi Kenyalang , Sarawak is situated on the north-west of the island. It is the largest state in Malaysia followed by Sabah, the second largest state located to the North- East.The administrative capital is Kuching, which...
. As such, virtually all plants in cultivation up to that time under the name N. pilosa actually represented N. chaniana
Nepenthes chaniana
Nepenthes chaniana ]]) is a highland pitcher plant species belonging to the genus Nepenthes. It is characterised by a dense indumentum of long, white hairs. Pitchers are cylindrical and mostly white to yellow in colouration....
.
Description
Nepenthes pilosa is a climbing plant. The stem may reach a length of more than 7 m and is up to 9 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 up to 7 cm long and circular in cross section.
Leaves are petiolate and coriaceous or thin-coriaceous in texture. The lamina or leaf blade is obovate-lanceolate to lanceolate in shape. It measure up to 30 cm in length by 7.5 cm in width. The apex of the lamina is rounded or shortly acuminate and may be slightly peltate. The lamina is abruptly attenuate towards the base. The petiole
Petiole (botany)
In botany, the petiole is the stalk attaching the leaf blade to the stem. The petiole usually has the same internal structure as the stem. Outgrowths appearing on each side of the petiole are called stipules. Leaves lacking a petiole are called sessile, or clasping when they partly surround the...
is triangular and up to 6 mm wide. It is grooved and bears a pair of narrow wings that form an amplexicaul sheath around the stem and are decurrent for up to 2.5 cm, terminating abruptly in a rounded base. Four or five logitudinal veins are present on either side of the midrib. Pinnate veins are indistinct and irregularly reticulate. 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 usually around 1.5 to 2 times as long as the lamina.
Rosette and lower pitchers are ovate in the lower portion, becoming cylindrical above. They are up to 10 cm high by 4 cm wide and typically have prominent ribs on their ventral surface in place of wings. The pitcher mouth has an oblique insertion. 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 flattened and up to 7 mm wide at the rear. It bears a series of ribs spaced ⅓ to ¼ mm apart, which terminate in short teeth that are barely longer than they are broad. 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 the ventricose portion of the pitcher's inner surface. The digestive glands are overarched and number 600 to 700 per square centimetre. 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 roughly orbicular, subcordate, and around 2.5 cm long by 2.5 cm wide. It is relatively flat, although it has a central keel in its basal part. Extrafloral nectaries are scattered on the underside of the lid, becoming smaller and more numerous towards the margins.
Upper pitchers gradually arise from the ends of the tendrils, forming a 15 to 20 mm wide curve. They are infundibular in shape and reach much greater dimensions than their lower counterparts, measuring up to 18 cm high by 8 cm wide. Like terrestrial pitchers, they lack wings, instead having a pair of prominent ribs. The pitcher mouth is positioned almost horizontally at the front, but rises into a neck (≤3 cm high) towards the rear. The flattened peristome is up to 12 mm wide and bears ribs spaced ⅓ mm apart which terminate in short teeth. Virtually the entire inner surface of the pitcher is glandular, having very small overarched glands at a density of 2000 to 2500 per square centimetre. The pitcher lid suborbicular, deeply cordate, and measures up to 7 cm in length. Small round glands are scattered throughout the lower surface of the lid and a prominent hook-like crest is present near the base.
Nepenthes pilosa has a conspicuous 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 yellow-brown hairs. This covering is particularly dense on developing parts and on the underside of the lamina in mature leaves. It is notably absent from the upper surface of the lamina.
Herbarium specimens dry to a reddish-brown colour on the stem and the underside of the leaves, while the upper surface of the lamina is typically fallow
Fallow (color)
Fallow is a pale brown color that is the color of sandy soil in fallow fields.Fallow is one of the oldest color names in English. The first recorded use of fallow as a color name in English was in the year 1000...
.
Ecology
Nepenthes pilosa is endemic to the mountain rangeMountain range
A mountain range is a single, large mass consisting of a succession of mountains or narrowly spaced mountain ridges, with or without peaks, closely related in position, direction, formation, and age; a component part of a mountain system or of a mountain chain...
of Bukit Batu Lesung (likely synonymous with Ketang Lesung) in East Kalimantan
East Kalimantan
East Kalimantan is the second largest Indonesian province, located on the Kalimantan region on the east of Borneo island. The resource-rich province has two major cities, Samarinda and Balikpapan...
, 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....
. The mountain has been described as a "long sandstone
Sandstone
Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...
ridge with several small peaks". The typical habitat of this species is mossy forest. A population of approximately 200 plants has been found growing at an elevation of around 1600 or 1700 m.
Nepenthes pilosa is classified 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...
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.
Related species
Nepenthes pilosa is easily distinguished from most other species in the genus on the basis of its hook-shaped lid appendage. The only other Bornean Nepenthes species with a similarly developed appendage are N. burbidgeaeNepenthes burbidgeae
Nepenthes burbidgeae , also known as the painted pitcher plant or Burbidge's Pitcher-Plant, is a tropical pitcher plant with a patchy distribution around Mount Kinabalu and neighbouring Mount Tambuyukon in Sabah, Borneo.-Botanical history:...
and N. chaniana
Nepenthes chaniana
Nepenthes chaniana ]]) is a highland pitcher plant species belonging to the genus Nepenthes. It is characterised by a dense indumentum of long, white hairs. Pitchers are cylindrical and mostly white to yellow in colouration....
.
B. H. Danser
B. H. Danser
Benedictus Hubertus Danser , often abbreviated B. H. Danser, was a Dutch taxonomist and botanist...
suggested that N. pilosa is most closely related to N. burbidgeae and, prior to the rediscovery of wild populations of N. pilosa, the species was considered a possible heterotypic synonym of N. burbidgeae by some authors. N. pilosa differs in having a more prominent and extensive 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...
.
Compared to N. chaniana, the pitchers of N. pilosa are more cylindrical, squater, and not as laterally-compressed.
Nepenthes glandulifera
Nepenthes glandulifera
Nepenthes glandulifera is a species of pitcher plant endemic to the Hose Mountains of central Sarawak. This plant is so named for the black speckles around the petioles. The species's discoverer, Ch'ien Lee, initially thought they were a sign of disease. After further investigation, it was...
has a similarly extensive indumentum, but lacks a well-developed lid appendage and bears many prominent extrafloral nectaries.
Natural hybrids
No natural hybrids involving N. pilosa have been recorded. Some older publications list crosses with 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...
and N. veitchii
Nepenthes veitchii
Nepenthes veitchii |James Veitch]], nurseryman of the Veitch Nurseries), or Veitch's Pitcher-Plant, is a Nepenthes species from the island of Borneo. The plant is widespread in north-western Borneo and can also be found in parts of Kalimantan. N...
, but the latter is now known to involve N. chaniana
Nepenthes chaniana
Nepenthes chaniana ]]) is a highland pitcher plant species belonging to the genus Nepenthes. It is characterised by a dense indumentum of long, white hairs. Pitchers are cylindrical and mostly white to yellow in colouration....
instead of N. pilosa, while the former is thought to represent the cross N. fusca
Nepenthes fusca
Nepenthes fusca , or the Dusky Pitcher-Plant, is a tropical pitcher plant endemic to Borneo. It is found throughout a wide altitudinal range and is almost always epiphytic in nature, primarily growing in mossy forest....
× N. lowii.
