Nepenthes hurrelliana
Encyclopedia
Nepenthes hurrelliana is a tropical pitcher plant
endemic to Borneo
, where it has been recorded from northern Sarawak
, southwestern Sabah
, and Brunei
. It is of putative hybrid origin; its two original parent species are thought to be N. fusca
and N. veitchii
. A thick indumentum
of rusty-brown hairs covers the entire plant, a characteristic presumably inherited from the latter.
, a form of N. maxima
, or a natural hybrid. In 1988, Anthea Phillipps
and Anthony Lamb
published an illustration of a N. hurrelliana specimen from Mount Murud
under the name "N. veitchii
× N. fusca
". However, in their 1996 monograph, Pitcher-Plants of Borneo
, the authors treated it as an undescribed species, "Nepenthes sp.". The taxon
was also listed as an undescribed species, "Nepenthes sp. B", in Charles Clarke
's Nepenthes of Borneo
(1997) and Hugo Steiner
's Borneo: Its Mountains and Lowlands with their Pitcher Plants (2002).
In "Nepenthes of Gunung Murud", an article published in a 1996 issue of the Carnivorous Plant Newsletter
, John De Witte describes a hybrid "most probably between N. veitchii and N. stenophylla
or N. fusca", which likely represents this species.
In 1999, Bruce Salmon proposed that this taxon might be conspecific with the enigmatic N. mollis
, of which only a single pitcherless specimen is known. This interpretation was not followed by Martin Cheek
and Anthony Lamb
, who formally described
N. hurrelliana in 2003. The type specimen, A.Lamb & Surat 145/99, was collected on Mount Lumarku
in Sabah
and is deposited at the herbarium
of the Forest Department, Sandakan
(SAN).
Nepenthes hurrelliana is named after Andrew Hurrell, who studied the plant on Mount Murud in 1995 and whose field observations showed that it grew in self-sustaining populations independent of its putative parent species and could thus be considered a distinct species.
and several other mountains have internodes up to 10 cm long.
The leaves of the type form from Mount Lumarku
are up to 24 cm long and have a winged petiole
, which clasps the stem for about half of its circumference and is decurrent for around 1 cm. Plants from Mount Mulu
produce more narrowly lanceolate leaves with broadly winged petioles that are decurrent down the entire internode (≤10 cm long).
Rosette and lower pitchers are narrowly ovate to infundibular. They are large, growing to 30 cm in height. The lid or operculum
is broadly triangular in shape and has an undulating margin. The peristome forms an extended neck (≤9 cm long) at the rear and is up to 7 cm wide at this point.
Upper pitchers are more infundibular than their lower counterparts, but also reach large dimensions of up to 28.5 cm. In aerial pitchers, the lid is much more narrowly triangular. It measures up to 8 cm long by 4.2 cm wide and has a cordate base. It bears a hook-shaped basal crest and a filiform apical appendage up to 5 mm long. A number of large, scattered nectar gland
s are present on the underside of the lid, particularly along the margins and near the base.
Nepenthes hurrelliana has a racemose
inflorescence
. Pedicels
bear a basal bract
measuring 3 to 4 mm in length.
The dense reddish-brown indumentum
of N. hurrelliana is one of the most conspicuous of any Nepenthes species. The upper surface of the lid has rusty-brown hairs, while the lower surface only bears them along its margins. Unusually for Nepenthes, hairs are present even on the upper surface of the lamina and on the glandular crest of the lid.
Nepenthes hurrelliana is endemic to Borneo
, where it has been recorded from a number of mountains in northern Sarawak
, southwestern Sabah
, and Brunei
. Specifically, it has been found on Mount Lumarku
, Mount Mulu
, Mount Murud
, and mountains of the Meligan Range near Long Pasia (including Mount Rimau). It has a wide altitudinal distribution of 1300 to 2400 m above sea level. On Mount Murud (2423 m), N. hurrelliana is common on the summit ridge above 2100 m, but becomes rarer with increasing elevation as this brings with it more stunted and exposed vegetation. Populations from the summit ridge of Mount Lumarku (c.
1900 m) are extensive above 1620 m.
The typical habitat of N. hurrelliana is tall mossy forest and upper montane forest, where it usually grows as an epiphyte
up to 10 m off the ground. It has also been recorded from stunted mossy heath forest
. Some plants occur terrestrially, although these are less common.
Nepenthes hurrelliana plays host to a number of pitcher infauna
. One of the most conspicuous examples is a small golden-coloured frog
of the genus Philautus
, which has been observed in the pitchers of epiphytic N. hurrelliana on Mount Lumarku.
and N. veitchii
. This has led to speculation regarding the lineage of this species, with a number of authors suggesting a possible hybridogenic origin.
Botanist Clive A. Stace
writes that one may speak of "stabilised hybrids when they have developed a distributional, morphological or genetic set of characters which is no longer strictly related to that of its parents, [...] if the hybrid has become an independent, recognisable, self-producing unit, it is de facto a separate species". This would support the status of N. hurrelliana as a species, since populations of this taxon
appear to be stabilised and it is abundant where it does grow. Furthermore, it has never been found to be sympatric with either of its putative parent species. The hybrid may have locally outcompeted
its parent species and eventually replaced them. Another possibility is that it was dispersed to new areas where neither of the parent species were established.
Examples of other Nepenthes species with a putative hybrid origin include N. hamiguitanensis
, N. murudensis
, and N. petiolata
.
The lower pitchers of N. hurrelliana are distinctive, but the upper ones bear a close resemblance to those of N. fusca
. Of the Bornean
pitcher plant
flora, only these two species have such a narrowly triangular lid. The upper pitchers of N. hurrelliana differ in having a horizontal mouth that rises abruptly into a long neck at the back and in having a hirsute basal crest on the underside of the lid.
Nepenthes hurrelliana is particularly similar to a form of N. fusca from the southern portion of the Crocker Range
in Sabah
. This form exhibits a wider peristome, longer neck, and a more triangular lid than most other examples of the species. However, the peristome is still not as well developed as in N. hurrelliana and the plant lacks the dense indumentum of the latter. Furthermore, N. hurrelliana differs in the distribution of nectar glands on the lower surface of its lid.
Nepenthes hurrelliana may also be confused with its other putative parent species, N. veitchii
. The two taxa
differ markedly in growth habit and N. hurrelliana has more infundibular pitchers with distinctive purple speckles as well as a differently shaped lid.
The species has also been compared to N. maxima
, although the latter is now known to be absent from Borneo
.
of N. hurrelliana are reminiscent of N. mollis
and it has been suggested that the two species may be conspecific. Bruce Salmon wrote that the type specimen of N. mollis differs from the Mount Lumarku
form of N. hurrelliana in lacking bract
eate pedicels
and in having a decurrent leaf base with wings up to 6 cm long (as opposed to 1 to 2 cm in N. hurrelliana).
Some authors consider the hypothesis equating these two species to be "rather improbable". An editor's note by Jan Schlauer accompanying Salmon's article cautions that specimens from the type locality of N. mollis must be examined before the two taxa are united:
If N. mollis and N. hurrelliana were shown to be conspecific, the latter would become a heterotypic synonym
of the former.
and N. veitchii
.
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....
, where it has been recorded from northern 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...
, southwestern 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 Brunei
Brunei
Brunei , officially the State of Brunei Darussalam or the Nation of Brunei, the Abode of Peace , is a sovereign state located on the north coast of the island of Borneo, in Southeast Asia...
. It is of putative hybrid origin; its two original parent species are thought to be 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....
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...
. A thick 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 rusty-brown hairs covers the entire plant, a characteristic presumably inherited from the latter.
Botanical history
Nepenthes hurrelliana was known to botanists for some time prior to its description, although authors differed as to its identity, with most treating it as either a form of N. veitchiiNepenthes 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...
, a form of 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....
, or a natural hybrid. In 1988, 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...
published an illustration of a N. hurrelliana specimen from Mount Murud
Mount Murud
Mount Murud or Muru is a sandstone mountain located in the Malaysian part of Borneo. At 2,423 m , it is the highest mountain in the state of Sarawak....
under the name "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...
× 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....
". However, in their 1996 monograph, 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...
, the authors treated it as an undescribed species, "Nepenthes sp.". The taxon
Taxon
|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...
was also listed as an undescribed species, "Nepenthes sp. B", in 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...
's 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"...
(1997) and Hugo Steiner
Hugo Steiner
Hugo Steiner is a Swiss citizen who graduated from the University of Zurich as a physician specialising in endocrinology. He worked for several years as the leader of a research group in experimental endocrinology for Hoffmann-La Roche Ltd in Basel, Switzerland. He has also done research work in...
's Borneo: Its Mountains and Lowlands with their Pitcher Plants (2002).
In "Nepenthes of Gunung Murud", an article published in a 1996 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:...
, John De Witte describes a hybrid "most probably between N. veitchii and N. stenophylla
Nepenthes stenophylla
Nepenthes stenophylla , or the Narrow-Leaved Pitcher-Plant, is a tropical pitcher plant endemic to Borneo. The species produces attractive funnel-shaped pitchers up to 25 cm high...
or N. fusca", which likely represents this species.
In 1999, Bruce Salmon proposed that this taxon might be conspecific with the enigmatic N. mollis
Nepenthes mollis
Nepenthes mollis , or the Velvet Pitcher-Plant, is a tropical pitcher plant species native to Kalimantan, Borneo. It is known only from a single dried herbarium specimen and is the sole recognised species in the genus Nepenthes of which the pitchers are unknown.The habitat of N. mollis is listed as...
, of which only a single pitcherless specimen is known. This interpretation was not followed by 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,...
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...
, who 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. hurrelliana in 2003. The type specimen, A.Lamb & Surat 145/99, was collected on Mount Lumarku
Mount Lumarku
Mount Lumarku or Lumaku is a mountain in southwestern Sabah. The pitcher plant species Nepenthes fusca, Nepenthes hurrelliana, and Nepenthes tentaculata are native to this mountain....
in 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 is deposited at 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 Forest Department, Sandakan
Sandakan
Sandakan is the second-largest city in Sabah, East Malaysia, on the north-eastern coast of Borneo. It is located on the east coast of the island and it is the administrative centre of Sandakan Division and was the former capital of British North Borneo...
(SAN).
Nepenthes hurrelliana is named after Andrew Hurrell, who studied the plant on Mount Murud in 1995 and whose field observations showed that it grew in self-sustaining populations independent of its putative parent species and could thus be considered a distinct species.
Description
Nepenthes hurrelliana is a climbing plant. Forms from different localities vary slightly in morphology. Plants from Mount MuluMount Mulu
Mount Mulu is a sandstone and shale mountain. At 2376 m, it is the second highest mountain in the state of Sarawak, after Mount Murud. It is located within the boundaries of Gunung Mulu National Park, which is named after it....
and several other mountains have internodes up to 10 cm long.
Mount Lumarku
Mount Lumarku or Lumaku is a mountain in southwestern Sabah. The pitcher plant species Nepenthes fusca, Nepenthes hurrelliana, and Nepenthes tentaculata are native to this mountain....
are up to 24 cm long and have a winged 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...
, which clasps the stem for about half of its circumference and is decurrent for around 1 cm. Plants from Mount Mulu
Mount Mulu
Mount Mulu is a sandstone and shale mountain. At 2376 m, it is the second highest mountain in the state of Sarawak, after Mount Murud. It is located within the boundaries of Gunung Mulu National Park, which is named after it....
produce more narrowly lanceolate leaves with broadly winged petioles that are decurrent down the entire internode (≤10 cm long).
Rosette and lower pitchers are narrowly ovate to infundibular. They are large, growing to 30 cm in height. The lid or operculum
Operculum (botany)
An operculum, in botany, is a term generally used to describe a structure within a plant, moss, or fungus acting as a cap, flap, or lid. In plants, it may also be called a bud cap.Examples of structures identified as opercula include:...
is broadly triangular in shape and has an undulating margin. The peristome forms an extended neck (≤9 cm long) at the rear and is up to 7 cm wide at this point.
Upper pitchers are more infundibular than their lower counterparts, but also reach large dimensions of up to 28.5 cm. In aerial pitchers, the lid is much more narrowly triangular. It measures up to 8 cm long by 4.2 cm wide and has a cordate base. It bears a hook-shaped basal crest and a filiform apical appendage up to 5 mm long. A number of large, scattered nectar 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 :...
s are present on the underside of the lid, particularly along the margins and near the base.
Nepenthes hurrelliana 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...
. 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....
bear a basal 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...
measuring 3 to 4 mm in length.
The dense reddish-brown 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 N. hurrelliana is one of the most conspicuous of any Nepenthes species. The upper surface of the lid has rusty-brown hairs, while the lower surface only bears them along its margins. Unusually for Nepenthes, hairs are present even on the upper surface of the lamina and on the glandular crest of the lid.
Ecology
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....
, where it has been recorded from a number of mountains in northern 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...
, southwestern 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 Brunei
Brunei
Brunei , officially the State of Brunei Darussalam or the Nation of Brunei, the Abode of Peace , is a sovereign state located on the north coast of the island of Borneo, in Southeast Asia...
. Specifically, it has been found on Mount Lumarku
Mount Lumarku
Mount Lumarku or Lumaku is a mountain in southwestern Sabah. The pitcher plant species Nepenthes fusca, Nepenthes hurrelliana, and Nepenthes tentaculata are native to this mountain....
, Mount Mulu
Mount Mulu
Mount Mulu is a sandstone and shale mountain. At 2376 m, it is the second highest mountain in the state of Sarawak, after Mount Murud. It is located within the boundaries of Gunung Mulu National Park, which is named after it....
, Mount Murud
Mount Murud
Mount Murud or Muru is a sandstone mountain located in the Malaysian part of Borneo. At 2,423 m , it is the highest mountain in the state of Sarawak....
, and mountains of the Meligan Range near Long Pasia (including Mount Rimau). It has a wide altitudinal distribution of 1300 to 2400 m above sea level. On Mount Murud (2423 m), N. hurrelliana is common on the summit ridge above 2100 m, but becomes rarer with increasing elevation as this brings with it more stunted and exposed vegetation. Populations from the summit ridge of Mount Lumarku (c.
Circa
Circa , usually abbreviated c. or ca. , means "approximately" in the English language, usually referring to a date...
1900 m) are extensive above 1620 m.
The typical habitat of N. hurrelliana is tall mossy forest and upper montane forest, where it usually 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...
up to 10 m off the ground. It has also been recorded from stunted mossy heath forest
Heath forest
Heath forest is a type of tropical moist forest found in areas with acidic, sandy soils that are extremely nutrient-poor. Notable examples are the Rio Negro campinarana of the Amazon Basin in South America, and the Sundaland heath forests of Borneo and neighboring islands.-External links:**...
. Some plants occur terrestrially, although these are less common.
Nepenthes hurrelliana plays host to a number of pitcher infauna
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...
. One of the most conspicuous examples is a small golden-coloured frog
Frog
Frogs are amphibians in the order Anura , formerly referred to as Salientia . Most frogs are characterized by a short body, webbed digits , protruding eyes and the absence of a tail...
of the genus Philautus
Philautus
Philautus is a genus of shrub frogs in the family Rhacophoridae. Some species in this genus are now considered extinct by IUCN, while others are widespread and abundant...
, which has been observed in the pitchers of epiphytic N. hurrelliana on Mount Lumarku.
Hybrid origin
The pitchers of N. hurrelliana are roughly intermediate in appearance between those of N. fuscaNepenthes 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....
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...
. This has led to speculation regarding the lineage of this species, with a number of authors suggesting a possible hybridogenic origin.
Botanist Clive A. Stace
Clive A. Stace
Clive Anthony Stace is a British botanist and botanical author. His academic career was based at the University of Leicester, where he held the post of Professor of Plant taxonomy...
writes that one may speak of "stabilised hybrids when they have developed a distributional, morphological or genetic set of characters which is no longer strictly related to that of its parents, [...] if the hybrid has become an independent, recognisable, self-producing unit, it is de facto a separate species". This would support the status of N. hurrelliana as a species, since populations of this 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...
appear to be stabilised and it is abundant where it does grow. Furthermore, it has never been found to be sympatric with either of its putative parent species. The hybrid may have locally outcompeted
Competition (biology)
Competition is an interaction between organisms or species, in which the fitness of one is lowered by the presence of another. Limited supply of at least one resource used by both is required. Competition both within and between species is an important topic in ecology, especially community ecology...
its parent species and eventually replaced them. Another possibility is that it was dispersed to new areas where neither of the parent species were established.
Examples of other Nepenthes species with a putative hybrid origin include N. hamiguitanensis
Nepenthes hamiguitanensis
Nepenthes hamiguitanensis is a tropical pitcher plant endemic to a single peak on the Philippine island of Mindanao, where it grows at elevations of 1200–1600 m above sea level. Once thought to be a natural hybrid between N. micramphora and N. peltata, this plant is now considered a...
, N. murudensis
Nepenthes murudensis
Nepenthes murudensis , or the Murud Pitcher-Plant, is a tropical pitcher plant endemic to Mount Murud in Borneo, after which it is named. It is of putative hybrid origin: its two original parent species are thought to be N. reinwardtiana and N...
, and N. petiolata
Nepenthes petiolata
Nepenthes petiolata is a highland Nepenthes pitcher plant species endemic to Mindanao island in the Philippines, where it grows at an elevation of 1450–1900 m above sea level.-Natural hybrids:*? N. alata × N. petiolata...
.
Related species
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....
. Of the Bornean
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....
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...
flora, only these two species have such a narrowly triangular lid. The upper pitchers of N. hurrelliana differ in having a horizontal mouth that rises abruptly into a long neck at the back and in having a hirsute basal crest on the underside of the lid.
Nepenthes hurrelliana is particularly similar to a form of N. fusca from the southern portion of the 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...
in 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...
. This form exhibits a wider peristome, longer neck, and a more triangular lid than most other examples of the species. However, the peristome is still not as well developed as in N. hurrelliana and the plant lacks the dense indumentum of the latter. Furthermore, N. hurrelliana differs in the distribution of nectar glands on the lower surface of its lid.
Nepenthes hurrelliana may also be confused with its other putative parent species, 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...
. 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...
differ markedly in growth habit and N. hurrelliana has more infundibular pitchers with distinctive purple speckles as well as a differently shaped lid.
The species has also been compared to 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....
, although the latter is now known to be absent from 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....
.
Nepenthes mollis
The attenuate leaf attachment and dense indumentumIndumentum
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 N. hurrelliana are reminiscent of N. mollis
Nepenthes mollis
Nepenthes mollis , or the Velvet Pitcher-Plant, is a tropical pitcher plant species native to Kalimantan, Borneo. It is known only from a single dried herbarium specimen and is the sole recognised species in the genus Nepenthes of which the pitchers are unknown.The habitat of N. mollis is listed as...
and it has been suggested that the two species may be conspecific. Bruce Salmon wrote that the type specimen of N. mollis differs from the Mount Lumarku
Mount Lumarku
Mount Lumarku or Lumaku is a mountain in southwestern Sabah. The pitcher plant species Nepenthes fusca, Nepenthes hurrelliana, and Nepenthes tentaculata are native to this mountain....
form of N. hurrelliana in lacking 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...
eate 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....
and in having a decurrent leaf base with wings up to 6 cm long (as opposed to 1 to 2 cm in N. hurrelliana).
Some authors consider the hypothesis equating these two species to be "rather improbable". An editor's note by Jan Schlauer accompanying Salmon's article cautions that specimens from the type locality of N. mollis must be examined before the two taxa are united:
The identity of the specimens from G. Lumarku with N. mollis should be proven by comparison with authentic pitchered material from G. Kemul. Unless this is done, the data above cannot be taken as an emendation of Danser's original description of N. mollis but are only referring to north Bornean plants without doubt.
If N. mollis and N. hurrelliana were shown to be conspecific, the latter would become a heterotypic synonym
Synonym (taxonomy)
In scientific nomenclature, a synonym is a scientific name that is or was used for a taxon of organisms that also goes by a different scientific name. For example, Linnaeus was the first to give a scientific name to the Norway spruce, which he called Pinus abies...
of the former.
Natural hybrids
To date, the only known natural hybrids involving N. hurrelliana are rare 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...
.