Nepenthes hamiguitanensis
Encyclopedia
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 species of possible hybridogenic origin. It produces squat upper pitchers that vary greatly in pigmentation, from red speckled to yellow throughout.
The specific epithet hamiguitanensis is derived from the name of Mount Hamiguitan
, to which it is endemic, and the Latin
ending -ensis, meaning "from".
in 2010, this taxon
was already known several years earlier. A herbarium specimen of N. hamiguitanensis was collected by Victor B. Amoroso and R. Aspiras on March 13, 2007, from the Mount Hamiguitan
summit ridge, specifically the trail leading to San Isidro
. This plant was growing in montane forest margins at an altitude of 1310 m. Designated as V.Amoroso & R.Aspiras CMUH00006494, the specimen is deposited at the Central Mindanao University Herbarium
(CMUH) in Musuan
, Bukidnon
, Mindanao
, Philippines
.
Thomas Gronemeyer, Volker Heinrich
and Stewart McPherson
carried out field studies on N. hamiguitanensis and the other species of Mount Hamiguitan between July 22–24, 2008. The taxon was subsequently identified as a natural hybrid between N. micramphora
and N. peltata
in McPherson's two-volume monograph, Pitcher Plants of the Old World
, published in May 2009.
Gronemeyer returned to the site with Andreas Wistuba
between February 13 and 14, 2010. Numerous seedlings and mature, climbing plants of N. hamiguitanensis were observed, but no intermediate plants with lower pitchers were found. These field studies on Mount Hamiguitan also included observations of N. micramphora
, N. mindanaoensis
, and N. peltata
.
Nepenthes hamiguitanensis was formally described
by Thomas Gronemeyer, Andreas Wistuba
, Volker Heinrich
, Stewart McPherson
, François Mey, and Victor B. Amoroso, in the second volume of McPherson's Carnivorous Plants and their Habitats, published in July 2010. The herbarium specimen V.Amoroso & R.Aspiras CMUH00006494 was designated as the holotype
.
is cylindrical and 8–10 mm in diameter in mature plants; internodes are 4–7 cm long.
Leaves of the climbing stem are petiolate. The lamina (leaf blade) is elliptic to oblong and measures up to 25 cm in length by 9 cm width. It has an obtuse apex, while the base is gradually attenuate, forming a canaliculate, sessile petiole
up to 9 cm long. Three longitudinal veins are present on either side of the midrib. Pinnate veins are numerous and run obliquely to the laminar margin. Tendril
s are often approximately the same length as the lamina; those bearing upper pitchers are often curled.
In the wild, no adult lower pitchers were recorded, only rosette
pitchers on seedling plants. For this reason they were not covered in the formal description.
Upper pitchers are infundibular in the basal half and cylindrical to slightly infundibular above. A prominent hip and waist (constriction) delimits these two halves. These aerial traps are up to 20 cm high by 9 cm wide. Wings are reduced to a pair of ribs on the ventral surface of the pitcher cup. The pitcher mouth (≤8 cm wide) has an oblique insertion and rises towards the rear, forming a short neck. The peristome
is typically cylindrical but may sometimes be slightly flattened. It is up to 1 cm wide and bears ribs spaced 0.3 mm apart, which terminate in short teeth (≤1 mm long) on the inner margin. The gland
ular or digestive region covers the lower half of the pitcher's inner surface. The pitcher lid or operculum
is cordate and up to 5 cm wide. Nectaries are evenly distributed on the underside of the lid and a prominent appendage is present at the base of the lid's lower surface. A bifurcate spur (≤4 mm long) is inserted near the base of the lid. Upper pitchers are most commonly creamy white throughout, but may also be red speckled on a yellowish background. The peristome may be creamy white, red striped, or dark red.
Nepenthes hamiguitanensis has a racemose
inflorescence
. In the type description, the male inflorescence is recorded as being around 70 cm long by 3.5 cm wide and bearing two-flowered, ebracteate partial peduncles
. These measurements are taken from field observations carried out by the describing authors at the type locality on July 23, 2008, since herbarium material of the floral structures could not be located.
An coarse indumentum
of short, light brown to white hairs is present on all plant parts, being particularly prominent at the laminar margins.
in San Isidro
, Davao Oriental
, Mindanao
, Philippines
. It has an altitudinal distribution of 1200–1600 m above sea level, being particularly common at elevations above 1400 m.
The species grows terrestrially in primary montane forest and forest margins. It is not found in the so-called Bonsai Forest
, a region of stunted vegetation on the plateau
below the summit ridge of Mount Hamiguitan. It typically grows in partial shade and is frequently exposed to heavy downpours. While Mount Hamiguitan is an ultramafic mountain, N. hamiguitanensis does not necessarily grow in an ultramafic substrate, owing to the high humus content of the forest underlayer. At the type locality, N. hamiguitanensis occurs at an average density of around two to three plants per 50 m2, as estimated by eye. Only seedlings and mature, climbing plants have been observed, with no records of larger rosette
plants bearing lower pitchers.
Nepenthes hamiguitanensis is sympatric
with N. mindanaoensis
and grows in the same altitudinal range as N. micramphora
and N. peltata
; the latter two species are typically found in more open areas, where they are exposed to higher levels of incident light. Despite this, no natural hybrids involving N. hamiguitanensis have been observed with certainty; it has been suggested that the flowering times of N. hamiguitanensis and the other Nepenthes species of Mount Hamiguitan may differ.
The describing authors assessed the conservation status
of N. hamiguitanensis as Vulnerable
based on the IUCN criteria. They pointed out that N. hamiguitanensis is far more localised than N. micramphora and N. peltata, which occur at several sites on the mountain and are represented by larger populations. Mount Hamiguitan forms part of the Mount Hamiguitan Range Wildlife Sanctuary National Park and visitors are only permitted to climb the mountain with the assistance of a guide. The future of wild populations of N. hamiguitanensis will be further secured if provincial officials of Davao Oriental
are successful in their bid to gain recognition of Mount Hamiguitan as a UNESCO
World Heritage Site
.
and N. peltata
, both of which are also present on the upper slopes of Mount Hamiguitan
. It shares several morphological features with its putative parent species, such as the shape of the pitchers (with N. micramphora) and form of the indumentum
(with N. peltata). However, it has distinctive light-coloured upper pitchers that neither of these species possess (N. peltata is not known to produce aerial traps at all). In addition, N. hamiguitanensis inhabits a different ecological niche
to either of these species; it typically grows in partial shade under the cover of mountain forest or at forest margins, whereas N. micramphora and N. peltata are commonly found in more exposed sites.
Wild populations of N. hamiguitanensis appear to be stabilised as well as relatively homogeneous, with no intergrades observed. The species is thought to be self-sustaining and to reproduce independently of its putative parent species, as numerous seedlings have been found at the type locality. Taking these factors into account, the describing authors wrote: "we feel that a recent hybridisation event is unlikely and that Nepenthes hamiguitanensis is not in the earlier stages of specification".
Examples of other Nepenthes species with a putative hybrid origin include N. hurrelliana
, N. murudensis
, and N. petiolata
.
, N. mindanaoensis
, and N. peltata
, which they described as "closely related species". Nepenthes micramphora is smaller in all respects and is mostly glabrous (apart from the inflorescence
). Nepenthes mindanaoensis differs clearly in the shape of its upper pitchers, which are far more elongated. In addition, the species has an acute (or narrowly obtuse) laminar apex as compared to the obtuse apex of N. hamiguitanensis. Nepenthes peltata can be distinguished on the basis of its distinct pitchers and peltate tendril insertion. Also, unlike N. peltata, N. hamiguitanensis readily produces upper pitchers and a climbing stem.
may represent crosses involving it and N. micramphora
, N. mindanaoensis
, and N. peltata
.
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 a single peak on the Philippine
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
island of Mindanao
Mindanao
Mindanao is the second largest and easternmost island in the Philippines. It is also the name of one of the three island groups in the country, which consists of the island of Mindanao and smaller surrounding islands. The other two are Luzon and the Visayas. The island of Mindanao is called The...
, where it grows at elevations of 1200–1600 m above sea level. Once thought to be a natural hybrid between N. micramphora
Nepenthes micramphora
Nepenthes micramphora is a tropical pitcher plant known only from Mount Hamiguitan on the island of Mindanao in the Philippines. It is a highland plant growing at elevations of 1100–1635 m....
and N. peltata
Nepenthes peltata
Nepenthes peltata is a tropical pitcher plant known only from the upper slopes of Mount Hamiguitan on the island of Mindanao in the Philippines. It is characterised by a peltate tendril attachment and conspicuous indumentum...
, this plant is now considered a species of possible hybridogenic origin. It produces squat upper pitchers that vary greatly in pigmentation, from red speckled to yellow throughout.
The specific epithet hamiguitanensis is derived from the name of Mount Hamiguitan
Mount Hamiguitan
Mount Hamiguitan is a mountain located in the province of Davao Oriental. It has a height of 1,620 meters . The mountain and its vicinity has one of the most diverse wildlife populations in the Philippines. Among the wildlife found in the area are Philippine eagles and several species of Nepenthes...
, to which it is endemic, 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 -ensis, meaning "from".
Botanical history
Although only formally describedSpecies 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 2010, 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...
was already known several years earlier. A herbarium specimen of N. hamiguitanensis was collected by Victor B. Amoroso and R. Aspiras on March 13, 2007, from the Mount Hamiguitan
Mount Hamiguitan
Mount Hamiguitan is a mountain located in the province of Davao Oriental. It has a height of 1,620 meters . The mountain and its vicinity has one of the most diverse wildlife populations in the Philippines. Among the wildlife found in the area are Philippine eagles and several species of Nepenthes...
summit ridge, specifically the trail leading to San Isidro
San Isidro, Davao Oriental
San Isidro is a 4th class municipality in the province of Davao Oriental, Philippines. It has a land area of 205 km². According to the 2000 census, it has a population of 31,705 people in 6,117 households....
. This plant was growing in montane forest margins at an altitude of 1310 m. Designated as V.Amoroso & R.Aspiras CMUH00006494, the specimen is deposited at the Central Mindanao University Herbarium
Central Mindanao University
Central Mindanao University is one of the two universities in the province of Bukidnon, Mindanao Island in the Philippines.-History:Central Mindanao University was transformed from a settlement of farm schools organized by the Americans. It started as the Mailag Industrial School in 1910 and...
(CMUH) in Musuan
Musuan
Musuan Peak or Mount Musuan , also known as Mount Calayo is an active volcano on the island of Mindanao in the Philippines. It is 4.5 kilometres south of the city of Valencia, province of Bukidnon, and 81 km southeast of Cagayan de Oro City....
, Bukidnon
Bukidnon
Bukidnon is a landlocked province of the Philippines located in the Northern Mindanao region. Its capital is Malaybalay City. The province borders, clockwise starting from the north, Misamis Oriental, Agusan del Sur, Davao del Norte, Cotabato, Lanao del Sur, and Lanao del Norte.Bukidnon is...
, Mindanao
Mindanao
Mindanao is the second largest and easternmost island in the Philippines. It is also the name of one of the three island groups in the country, which consists of the island of Mindanao and smaller surrounding islands. The other two are Luzon and the Visayas. The island of Mindanao is called The...
, Philippines
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
.
Thomas Gronemeyer, Volker Heinrich
Volker Heinrich
Volker B. Heinrich is a German naturalist.He studied horticultural sciences at the Technical University of Munich. A self-confessed "nepenthophile", he is a carnivorous plant enthusiast....
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....
carried out field studies on N. hamiguitanensis and the other species of Mount Hamiguitan between July 22–24, 2008. The taxon was subsequently identified as a natural hybrid between N. micramphora
Nepenthes micramphora
Nepenthes micramphora is a tropical pitcher plant known only from Mount Hamiguitan on the island of Mindanao in the Philippines. It is a highland plant growing at elevations of 1100–1635 m....
and N. peltata
Nepenthes peltata
Nepenthes peltata is a tropical pitcher plant known only from the upper slopes of Mount Hamiguitan on the island of Mindanao in the Philippines. It is characterised by a peltate tendril attachment and conspicuous indumentum...
in McPherson's two-volume monograph, 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...
, published in May 2009.
Gronemeyer returned to the site with Andreas Wistuba
Andreas Wistuba
Dr. Andreas Wistuba is a German taxonomist and botanist specialising in the carnivorous plant genera Heliamphora and Nepenthes. More than half of all known Heliamphora species have been described by Wistuba.-Publications:...
between February 13 and 14, 2010. Numerous seedlings and mature, climbing plants of N. hamiguitanensis were observed, but no intermediate plants with lower pitchers were found. These field studies on Mount Hamiguitan also included observations of N. micramphora
Nepenthes micramphora
Nepenthes micramphora is a tropical pitcher plant known only from Mount Hamiguitan on the island of Mindanao in the Philippines. It is a highland plant growing at elevations of 1100–1635 m....
, N. mindanaoensis
Nepenthes mindanaoensis
Nepenthes mindanaoensis is a species of pitcher plant endemic to coastal lateritic hills on Mindanao in the Philippines. It is very closely related to N. alata.-Natural hybrids:*N. alata × N. mindanaoensis...
, and N. peltata
Nepenthes peltata
Nepenthes peltata is a tropical pitcher plant known only from the upper slopes of Mount Hamiguitan on the island of Mindanao in the Philippines. It is characterised by a peltate tendril attachment and conspicuous indumentum...
.
Nepenthes hamiguitanensis 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...
by Thomas Gronemeyer, Andreas Wistuba
Andreas Wistuba
Dr. Andreas Wistuba is a German taxonomist and botanist specialising in the carnivorous plant genera Heliamphora and Nepenthes. More than half of all known Heliamphora species have been described by Wistuba.-Publications:...
, Volker Heinrich
Volker Heinrich
Volker B. Heinrich is a German naturalist.He studied horticultural sciences at the Technical University of Munich. A self-confessed "nepenthophile", he is a carnivorous plant enthusiast....
, 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....
, François Mey, and Victor B. Amoroso, in the second volume of McPherson's Carnivorous Plants and their Habitats, published in July 2010. The herbarium specimen V.Amoroso & R.Aspiras CMUH00006494 was designated as 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...
.
Description
Nepenthes hamiguitanensis is a climbing plant growing to a height of 4 m. The stemPlant 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...
is cylindrical and 8–10 mm in diameter in mature plants; internodes are 4–7 cm long.
Leaves of the climbing stem are petiolate. The lamina (leaf blade) is elliptic to oblong and measures up to 25 cm in length by 9 cm width. It has an obtuse apex, while the base is gradually attenuate, forming a canaliculate, sessile 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...
up to 9 cm long. Three longitudinal veins are present on either side of the midrib. Pinnate veins are numerous and run obliquely to the laminar margin. 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 often approximately the same length as the lamina; those bearing upper pitchers are often curled.
In the wild, no adult lower pitchers were recorded, only rosette
Rosette (botany)
In botany, a rosette is a circular arrangement of leaves, with all the leaves at a single height.Though rosettes usually sit near the soil, their structure is an example of a modified stem.-Function:...
pitchers on seedling plants. For this reason they were not covered in the formal description.
Upper pitchers are infundibular in the basal half and cylindrical to slightly infundibular above. A prominent hip and waist (constriction) delimits these two halves. These aerial traps are up to 20 cm high by 9 cm wide. Wings are reduced to a pair of ribs on the ventral surface of the pitcher cup. The pitcher mouth (≤8 cm wide) has an oblique insertion and rises towards the rear, forming a short neck. 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 typically cylindrical but may sometimes be slightly flattened. It is up to 1 cm wide and bears ribs spaced 0.3 mm apart, which terminate in short teeth (≤1 mm long) on the inner margin. 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 or digestive region covers the lower half of the pitcher's inner surface. 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 cordate and up to 5 cm wide. Nectaries are evenly distributed on the underside of the lid and a prominent appendage is present at the base of the lid's lower surface. A bifurcate spur (≤4 mm long) is inserted near the base of the lid. Upper pitchers are most commonly creamy white throughout, but may also be red speckled on a yellowish background. The peristome may be creamy white, red striped, or dark red.
Nepenthes hamiguitanensis 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...
. In the type description, the male inflorescence is recorded as being around 70 cm long by 3.5 cm wide and bearing two-flowered, ebracteate partial peduncles
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...
. These measurements are taken from field observations carried out by the describing authors at the type locality on July 23, 2008, since herbarium material of the floral structures could not be located.
An coarse indumentum
Indumentum
The indumentum is a covering of fine hairs or bristles on a plant or insect.In plants, the indumentum types are:*pubescent*hirsute*pilose*villous*tomentose*stellate*scabrous*scurfy...
of short, light brown to white hairs is present on all plant parts, being particularly prominent at the laminar margins.
Ecology
Nepenthes hamiguitanensis is endemic to the summit ridge of Mount HamiguitanMount Hamiguitan
Mount Hamiguitan is a mountain located in the province of Davao Oriental. It has a height of 1,620 meters . The mountain and its vicinity has one of the most diverse wildlife populations in the Philippines. Among the wildlife found in the area are Philippine eagles and several species of Nepenthes...
in San Isidro
San Isidro, Davao Oriental
San Isidro is a 4th class municipality in the province of Davao Oriental, Philippines. It has a land area of 205 km². According to the 2000 census, it has a population of 31,705 people in 6,117 households....
, Davao Oriental
Davao Oriental
Davao Oriental is a province of the Philippines located in the Davao Region in Mindanao. Its capital is Mati and borders Compostela Valley to the west, and Agusan del Sur and Surigao del Sur to the north. Davao Oriental is the easternmost province of the country with Pusan Point as the easternmost...
, Mindanao
Mindanao
Mindanao is the second largest and easternmost island in the Philippines. It is also the name of one of the three island groups in the country, which consists of the island of Mindanao and smaller surrounding islands. The other two are Luzon and the Visayas. The island of Mindanao is called The...
, Philippines
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
. It has an altitudinal distribution of 1200–1600 m above sea level, being particularly common at elevations above 1400 m.
The species grows terrestrially in primary montane forest and forest margins. It is not found in the so-called Bonsai Forest
Pygmy forest
A pygmy forest is a forest which, for pedological and geological reasons, contains only miniature trees. Pygmy forests may occur over various world locations with notable occurrences being noted in the literature of the: California coastal terraces and inner coastal mountains of Northern...
, a region of stunted vegetation on the plateau
Plateau
In geology and earth science, a plateau , also called a high plain or tableland, is an area of highland, usually consisting of relatively flat terrain. A highly eroded plateau is called a dissected plateau...
below the summit ridge of Mount Hamiguitan. It typically grows in partial shade and is frequently exposed to heavy downpours. While Mount Hamiguitan is an ultramafic mountain, N. hamiguitanensis does not necessarily grow in an ultramafic substrate, owing to the high humus content of the forest underlayer. At the type locality, N. hamiguitanensis occurs at an average density of around two to three plants per 50 m2, as estimated by eye. Only seedlings and mature, climbing plants have been observed, with no records of larger rosette
Rosette (botany)
In botany, a rosette is a circular arrangement of leaves, with all the leaves at a single height.Though rosettes usually sit near the soil, their structure is an example of a modified stem.-Function:...
plants bearing lower pitchers.
Nepenthes hamiguitanensis is sympatric
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. mindanaoensis
Nepenthes mindanaoensis
Nepenthes mindanaoensis is a species of pitcher plant endemic to coastal lateritic hills on Mindanao in the Philippines. It is very closely related to N. alata.-Natural hybrids:*N. alata × N. mindanaoensis...
and grows in the same altitudinal range as N. micramphora
Nepenthes micramphora
Nepenthes micramphora is a tropical pitcher plant known only from Mount Hamiguitan on the island of Mindanao in the Philippines. It is a highland plant growing at elevations of 1100–1635 m....
and N. peltata
Nepenthes peltata
Nepenthes peltata is a tropical pitcher plant known only from the upper slopes of Mount Hamiguitan on the island of Mindanao in the Philippines. It is characterised by a peltate tendril attachment and conspicuous indumentum...
; the latter two species are typically found in more open areas, where they are exposed to higher levels of incident light. Despite this, no natural hybrids involving N. hamiguitanensis have been observed with certainty; it has been suggested that the flowering times of N. hamiguitanensis and the other Nepenthes species of Mount Hamiguitan may differ.
The describing authors assessed the conservation status
Conservation status
The conservation status of a group of organisms indicates whether the group is still extant and how likely the group is to become extinct in the near future...
of N. hamiguitanensis as Vulnerable
Vulnerable species
On 30 January 2010, the IUCN Red List of Threatened Species identified 9694 Vulnerable species, subspecies and varieties, stocks and sub-populations.-References:...
based on the IUCN criteria. They pointed out that N. hamiguitanensis is far more localised than N. micramphora and N. peltata, which occur at several sites on the mountain and are represented by larger populations. Mount Hamiguitan forms part of the Mount Hamiguitan Range Wildlife Sanctuary National Park and visitors are only permitted to climb the mountain with the assistance of a guide. The future of wild populations of N. hamiguitanensis will be further secured if provincial officials of Davao Oriental
Davao Oriental
Davao Oriental is a province of the Philippines located in the Davao Region in Mindanao. Its capital is Mati and borders Compostela Valley to the west, and Agusan del Sur and Surigao del Sur to the north. Davao Oriental is the easternmost province of the country with Pusan Point as the easternmost...
are successful in their bid to gain recognition of Mount Hamiguitan as a UNESCO
UNESCO
The United Nations Educational, Scientific and Cultural Organization is a specialized agency of the United Nations...
World Heritage Site
World Heritage Site
A UNESCO World Heritage Site is a place that is listed by the UNESCO as of special cultural or physical significance...
.
Hybrid origin
Nepenthes hamiguitanensis was initially assumed to represent a natural hybrid between N. micramphoraNepenthes micramphora
Nepenthes micramphora is a tropical pitcher plant known only from Mount Hamiguitan on the island of Mindanao in the Philippines. It is a highland plant growing at elevations of 1100–1635 m....
and N. peltata
Nepenthes peltata
Nepenthes peltata is a tropical pitcher plant known only from the upper slopes of Mount Hamiguitan on the island of Mindanao in the Philippines. It is characterised by a peltate tendril attachment and conspicuous indumentum...
, both of which are also present on the upper slopes of Mount Hamiguitan
Mount Hamiguitan
Mount Hamiguitan is a mountain located in the province of Davao Oriental. It has a height of 1,620 meters . The mountain and its vicinity has one of the most diverse wildlife populations in the Philippines. Among the wildlife found in the area are Philippine eagles and several species of Nepenthes...
. It shares several morphological features with its putative parent species, such as the shape of the pitchers (with N. micramphora) and form of 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...
(with N. peltata). However, it has distinctive light-coloured upper pitchers that neither of these species possess (N. peltata is not known to produce aerial traps at all). In addition, N. hamiguitanensis inhabits 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...
to either of these species; it typically grows in partial shade under the cover of mountain forest or at forest margins, whereas N. micramphora and N. peltata are commonly found in more exposed sites.
Wild populations of N. hamiguitanensis appear to be stabilised as well as relatively homogeneous, with no intergrades observed. The species is thought to be self-sustaining and to reproduce independently of its putative parent species, as numerous seedlings have been found at the type locality. Taking these factors into account, the describing authors wrote: "we feel that a recent hybridisation event is unlikely and that Nepenthes hamiguitanensis is not in the earlier stages of specification".
Examples of other Nepenthes species with a putative hybrid origin include N. hurrelliana
Nepenthes hurrelliana
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...
, 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
The describing authors compared N. hamiguitanensis to N. micramphoraNepenthes micramphora
Nepenthes micramphora is a tropical pitcher plant known only from Mount Hamiguitan on the island of Mindanao in the Philippines. It is a highland plant growing at elevations of 1100–1635 m....
, N. mindanaoensis
Nepenthes mindanaoensis
Nepenthes mindanaoensis is a species of pitcher plant endemic to coastal lateritic hills on Mindanao in the Philippines. It is very closely related to N. alata.-Natural hybrids:*N. alata × N. mindanaoensis...
, and N. peltata
Nepenthes peltata
Nepenthes peltata is a tropical pitcher plant known only from the upper slopes of Mount Hamiguitan on the island of Mindanao in the Philippines. It is characterised by a peltate tendril attachment and conspicuous indumentum...
, which they described as "closely related species". Nepenthes micramphora is smaller in all respects and is mostly glabrous (apart from the 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...
). Nepenthes mindanaoensis differs clearly in the shape of its upper pitchers, which are far more elongated. In addition, the species has an acute (or narrowly obtuse) laminar apex as compared to the obtuse apex of N. hamiguitanensis. Nepenthes peltata can be distinguished on the basis of its distinct pitchers and peltate tendril insertion. Also, unlike N. peltata, N. hamiguitanensis readily produces upper pitchers and a climbing stem.
Natural hybrids
Nepenthes hamiguitanensis has no confirmed natural hybrids, although certain plants from Mount HamiguitanMount Hamiguitan
Mount Hamiguitan is a mountain located in the province of Davao Oriental. It has a height of 1,620 meters . The mountain and its vicinity has one of the most diverse wildlife populations in the Philippines. Among the wildlife found in the area are Philippine eagles and several species of Nepenthes...
may represent crosses involving it and N. micramphora
Nepenthes micramphora
Nepenthes micramphora is a tropical pitcher plant known only from Mount Hamiguitan on the island of Mindanao in the Philippines. It is a highland plant growing at elevations of 1100–1635 m....
, N. mindanaoensis
Nepenthes mindanaoensis
Nepenthes mindanaoensis is a species of pitcher plant endemic to coastal lateritic hills on Mindanao in the Philippines. It is very closely related to N. alata.-Natural hybrids:*N. alata × N. mindanaoensis...
, and N. peltata
Nepenthes peltata
Nepenthes peltata is a tropical pitcher plant known only from the upper slopes of Mount Hamiguitan on the island of Mindanao in the Philippines. It is characterised by a peltate tendril attachment and conspicuous indumentum...
.