Nepenthes tobaica
Encyclopedia
Nepenthes tobaica is a tropical pitcher plant
endemic to Sumatra
. It is particularly abundant around Lake Toba
, after which it is named.
Nepenthes tobaica is closely related to N. angasanensis
, N. gracilis
, N. mikei
, and N. reinwardtiana
.
The earliest known collection of N. tobaica was made by Johannes Elias Teijsmann
on February 8, 1856, probably from the Batak
regions. This specimen, which includes female floral material, is H. L. B. 908,155-1106.
Matthew Jebb
and Martin Cheek
designated this specimen as the lectotype
of N. tobaica in their 1997 monograph.
Nepenthes tobaica was formally described
in 1928 by Dutch
botanist B. H. Danser
in his seminal monograph "The Nepenthaceae of the Netherlands Indies
". At the time, the species was already known from numerous herbarium specimens. Danser suggested a possibly conspecific species in N. reinwardtiana
:
In the scientific literature, N. tobaica has been confused with the closely related N. angasanensis
on several occasions. Nepenthes tobaica as described in Danser's 1940 description of N. densiflora
is actually N. angasanensis. Specimens identified as N. tobaica in Rusjdi Tamin and Mitsuru Hotta
's 1986 monograph on Sumatra
n Nepenthes actually represent both N. angasanensis and N. tobaica.
s are up to 25 cm long and often round in cross section. However, mature plants may have angular stems because of a groove that originates at the node and extends across most of the internode's length.
Leaves are coriaceous in texture and range from sessile to sub-petiolate. The shape of the lamina, or leaf blade, varies from oblong to spathulate. It measures up to 20 cm in length by 4 cm in width. The apical end of the lamina is typically rounded, but may be narrowed and obtuse. Robust plants sometimes have a sub-peltate tendril insertion. The lamina may be gradually or abruptly contracted towards the amplexicaul base, which clasps the stem for around half of its circumference. One to three longitudinal veins are present on either side of the midrib, although they are only prominent in robust specimens. Pinnate veins are indistinct. Tendril
s grow to 30 cm in length.
Rosette and lower pitchers are ovoid in the lower portion and cylindrical above. They are up to 20 cm high by 4 cm wide. A pair of wings runs down the pitcher's ventral surface, often bearing fringe elements either throughout the whole length or only in the upper part. The gland
ular region of the pitcher's inner surface is confined to the ovoid portion. A pair of "eye spots" is sometimes present on the inner surface, below the lid attachment. The pitcher mouth is ovate and has an oblique insertion. The narrow peristome
(≤5 mm wide) is cylindrical or slightly expanded and bears indistinct teeth. The pitcher lid or operculum
is ovate to sub-orbicular and has a somewhat cordate base. It lacks appendages. A spur
measuring up to 5 mm in length is inserted near the base of the lid. It may be unbranched, bifid, or trifid.
Upper pitchers are typically somewhat infundibular in the lowermost part, becoming narrowly ovoid in the lower third, and finally cylindrical and slightly narrower above. They may be quite large, reaching 25 cm in height by 5 cm in width. A pair of remnant ribs is present in place of the ventral wings. Other parts of aerial pitchers are similar to their lower counterparts.
Nepenthes tobaica has a racemose
inflorescence
. The peduncle
and rachis
can each grow to 20 cm in length. Partial peduncles are two-flowered and lack bract
eoles. In male inflorescences, the sepal
s are elliptic-obtuse, being slightly narrower in female ones. Around the town of Prapat, plants have been observed to come into flower in April, although mature fruit
s are not common at this time.
Nepenthes tobaica is characterised by an uneven indumentum
. Most mature vegetative parts are glabrous, although the midrib may bear persistent hairs. Groups of white, stellate hairs are often present in the leaf axils. The sepals of this species are densely tomentose, but the rest of the inflorescence has a sparser covering of short hairs.
In some forms, the underside of the lid is a vivid red, making the plants particularly easy to spot amongst other vegetation.
. Its natural range
was once thought to stretch from the Gayo Lands of Aceh
in the north to Tarutung
in the south. Towards the end of the 20th century, new locations of this species were discovered further south. These include Mount Sorik Merapi and a unique high altitude peat swamp habitat near Lake Kerinci
in Jambi. Charles Clarke
cites its altitudinal range as 380 to 1800 m above sea level, with a habitat near the port
town of Sibolga
constituting the lower extreme and Mount Pangulubao
the upper extreme. However, according to Matthew Jebb
and Martin Cheek
, N. tobaica can grow as high as 2750 m.
This species typically grows terrestrially in exposed areas. Nepenthes tobaica commonly grows in forest edges, where it is often sympatric with species of Leptospermum
and Rhodomyrtus
.
Nepenthes tobaica is very abundant in the Lake Toba
region, to the point where it is "difficult to avoid seeing it there". N. tobaica is also known to grow in high altitude peat swamp forest near Lake Kerinci
, at an altitude of 1100 m. At this location, the species grows alongside N. ampullaria
, N. gracilis
, N. mirabilis
, N. reinwardtiana
, and N. spathulata
. The Nepenthes species and hybrids at this site exhibit high levels of introgression
. The vegetation is dominated by species of the genera Rhododendron
and Melastoma
, as well as orchids and fern
s. It is very stunted and dense, with few trees exceeding 3 m in height. It is somewhat reminiscent of the highland heath forest
s around Bareo
in Sarawak
, Borneo
.
The conservation status
of N. tobaica is listed as Least Concern
on the 2006 IUCN Red List of Threatened Species
based on an assessment carried out in 2000.
.
The mite
species Creutzeria tobaica was described from the pitchers of a Java
nese Nepenthes identified as N. tobaica. However, N. tobaica has not been recorded outside of Sumatra.
In 2001, Charles Clarke
performed a cladistic analysis of the Nepenthes species of Sumatra and Peninsular Malaysia
using 70 morphological characteristics of each taxon. The following is a portion of the resultant cladogram
, showing part of "Clade 6". The sister pair of N. angasanensis and N. mikei has 79% support.
The pitchers of N. tobaica are similar to those of N. adnata
, although the stem and lamina are quite different.
, N. reinwardtiana
, N. rhombicaulis
, N. spathulata
, and N. spectabilis
.
Pitcher plant
Pitcher plants are carnivorous plants whose prey-trapping mechanism features a deep cavity filled with liquid known as a pitfall trap. It has been widely assumed that the various sorts of pitfall trap evolved from rolled leaves, with selection pressure favouring more deeply cupped leaves over...
endemic to Sumatra
Sumatra
Sumatra is an island in western Indonesia, westernmost of the Sunda Islands. It is the largest island entirely in Indonesia , and the sixth largest island in the world at 473,481 km2 with a population of 50,365,538...
. It is particularly abundant around Lake Toba
Lake Toba
Lake Toba is a lake and supervolcano. The lake is 100 kilometres long and 30 kilometres wide, and 505 metres at its deepest point. Located in the middle of the northern part of the Indonesian island of Sumatra with a surface elevation of about , the lake stretches from to...
, after which it is named.
Nepenthes tobaica is closely related to N. angasanensis
Nepenthes angasanensis
Nepenthes angasanensis is a highland Nepenthes pitcher plant species, native to Sumatra, where it grows at an altitude of 2200 to 2800 m. The status of this taxon is controversial as it is similar in morphology to N. mikei and N. tobaica.The specific epithet refers to Mount Puncak...
, N. gracilis
Nepenthes gracilis
Nepenthes gracilis , or the Slender Pitcher-Plant, is a very common lowland pitcher plant that is widespread in the Sunda region. It has been recorded from Borneo, Peninsular Malaysia, Singapore, central Sulawesi, Sumatra, and southernmost Thailand...
, N. mikei
Nepenthes mikei
Nepenthes mikei is a tropical pitcher plant endemic to Sumatra. It is characterised by its black mottled lower and upper pitchers. The species is closely related to N. angasanensis and N. tobaica....
, and N. reinwardtiana
Nepenthes reinwardtiana
Nepenthes reinwardtiana , Reinwardt's Pitcher-Plant, is a Nepenthes species found on the islands of Borneo and Sumatra. Although some sources have included Peninsular Malaysia and Singapore within the range of this species, these records appear to be erroneous.Nepenthes reinwardtiana has an...
.
Botanical history
Johannes Elias Teijsmann
Johannes Elias Teijsmann was a botanist and plant collector. He was born in Arnhem, Netherlands.Teijsmann travelled to Java in 1830 as Gardener of Governor General van den Bosch. He was appointed the Curator of the Buitenzorg Botanic Gardens the following year, a post he held until 1869...
on February 8, 1856, probably from the Batak
Batak (Indonesia)
Batak is a collective term used to identify a number of ethnic groups predominantly found in North Sumatra, Indonesia. The term is used to include the Toba, Karo, Pakpak, Simalungun, Angkola and Mandailing, each of which are distinct but related groups with distinct, albeit related, languages and...
regions. This specimen, which includes female floral material, is H. L. B. 908,155-1106.
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,...
designated this specimen as the lectotype
Lectotype
In botanical nomenclature and zoological nomenclature, a lectotype is a kind of name-bearing type. When a species was originally described on the basis of a name-bearing type consisting of multiple specimens, one of those may be designated as the lectotype...
of N. tobaica in their 1997 monograph.
Nepenthes tobaica 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...
". At the time, the species was already known from numerous herbarium specimens. Danser suggested a possibly conspecific species in N. reinwardtiana
Nepenthes reinwardtiana
Nepenthes reinwardtiana , Reinwardt's Pitcher-Plant, is a Nepenthes species found on the islands of Borneo and Sumatra. Although some sources have included Peninsular Malaysia and Singapore within the range of this species, these records appear to be erroneous.Nepenthes reinwardtiana has an...
:
"N. tobaica has only been found on the plateau north, east and south of Lake Toba. It is most closely related to N. Reinwardtiana and I am not quite certain, whether it is perhaps a form of this species, but up till now no intermediate forms have been discovered."
In the scientific literature, N. tobaica has been confused with the closely related N. angasanensis
Nepenthes angasanensis
Nepenthes angasanensis is a highland Nepenthes pitcher plant species, native to Sumatra, where it grows at an altitude of 2200 to 2800 m. The status of this taxon is controversial as it is similar in morphology to N. mikei and N. tobaica.The specific epithet refers to Mount Puncak...
on several occasions. Nepenthes tobaica as described in Danser's 1940 description of N. densiflora
Nepenthes densiflora
Nepenthes densiflora is a tropical pitcher plant endemic to Sumatra, where it grows at an altitude of between 1700 and 3200 m above sea level.No forms or varieties of N. densiflora have been described.-Taxonomy:...
is actually N. angasanensis. Specimens identified as N. tobaica in Rusjdi Tamin and Mitsuru Hotta
Mitsuru Hotta
is a Japanese botanist best known for his research on Araceae.Hotta was born in Osaka, Japan in 1937. He graduated from the Agricultural Department of Osaka Prefecture University in 1960. The same year, he took part in the Tonga and Fiji Expedition organised by Kyoto University...
's 1986 monograph on Sumatra
Sumatra
Sumatra is an island in western Indonesia, westernmost of the Sunda Islands. It is the largest island entirely in Indonesia , and the sixth largest island in the world at 473,481 km2 with a population of 50,365,538...
n Nepenthes actually represent both N. angasanensis and N. tobaica.
Description
Nepenthes tobaica is a climbing plant. The stem can attain a height of up to 7 m and is up to 6 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 25 cm long and often round in cross section. However, mature plants may have angular stems because of a groove that originates at the node and extends across most of the internode's length.
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 grow to 30 cm in length.
Rosette and lower pitchers are ovoid in the lower portion and cylindrical above. They are up to 20 cm high by 4 cm wide. A pair of wings runs down the pitcher's ventral surface, often bearing fringe elements either throughout the whole length or only in the upper part. 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 of the pitcher's inner surface is confined to the ovoid portion. A pair of "eye spots" is sometimes present on the inner surface, below the lid attachment. The pitcher mouth is ovate and has an oblique insertion. The narrow 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...
(≤5 mm wide) is cylindrical or slightly expanded and bears indistinct teeth. 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 ovate to sub-orbicular and has a somewhat cordate base. It lacks appendages. A spur
Spur (biology)
A spur in botany is a spike, usually part of a flower.In certain plants, part of a sepal or petal develops into an elongated hollow spike extending behind the flower, containing nectar which is sucked by long-tongued animals . Plants with such structures include Delphinium, Aquilegia, Piperia, and...
measuring up to 5 mm in length is inserted near the base of the lid. It may be unbranched, bifid, or trifid.
Nepenthes tobaica 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...
. The peduncle
Peduncle (botany)
In botany, a peduncle is a stem supporting an inflorescence, or after fecundation, an infructescence.The peduncle is a stem, usually green and without leaves, though sometimes colored or supporting small leaves...
and rachis
Rachis
Rachis is a biological term for a main axis or "shaft".-In zoology:In vertebrates a rachis can refer to the series of articulated vertebrae, which encase the spinal cord. In this case the rachis usually form the supporting axis of the body and is then called the spine or vertebral column...
can each grow to 20 cm in length. Partial peduncles are two-flowered and lack bract
Bract
In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis, or cone scale. Bracts are often different from foliage leaves. They may be smaller, larger, or of a different color, shape, or texture...
eoles. In male inflorescences, the sepal
Sepal
A sepal is a part of the flower of angiosperms . Collectively the sepals form the calyx, which is the outermost whorl of parts that form a flower. Usually green, sepals have the typical function of protecting the petals when the flower is in bud...
s are elliptic-obtuse, being slightly narrower in female ones. Around the town of Prapat, plants have been observed to come into flower in April, although mature fruit
Fruit
In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...
s are not common at this time.
Nepenthes tobaica is characterised by an uneven 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...
. Most mature vegetative parts are glabrous, although the midrib may bear persistent hairs. Groups of white, stellate hairs are often present in the leaf axils. The sepals of this species are densely tomentose, but the rest of the inflorescence has a sparser covering of short hairs.
In some forms, the underside of the lid is a vivid red, making the plants particularly easy to spot amongst other vegetation.
Ecology
Nepenthes tobaica is endemic to SumatraSumatra
Sumatra is an island in western Indonesia, westernmost of the Sunda Islands. It is the largest island entirely in Indonesia , and the sixth largest island in the world at 473,481 km2 with a population of 50,365,538...
. Its natural range
Range (biology)
In biology, the range or distribution of a species is the geographical area within which that species can be found. Within that range, dispersion is variation in local density.The term is often qualified:...
was once thought to stretch from the Gayo Lands of Aceh
Aceh
Aceh is a special region of Indonesia, located on the northern tip of the island of Sumatra. Its full name is Daerah Istimewa Aceh , Nanggroë Aceh Darussalam and Aceh . Past spellings of its name include Acheh, Atjeh and Achin...
in the north to Tarutung
Tarutung
Tarutung is a town in North Sumatra province of Indonesia and it is the seat of North Tapanuli Regency.Tarutung in Batak language means durian, because there was a lot of durian trees there....
in the south. Towards the end of the 20th century, new locations of this species were discovered further south. These include Mount Sorik Merapi and a unique high altitude peat swamp habitat near Lake Kerinci
Lake Kerinci
Lake Kerinci is a lake in Jambi, Indonesia. It is located at ....
in Jambi. 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...
cites its altitudinal range as 380 to 1800 m above sea level, with a habitat near the port
Port
A port is a location on a coast or shore containing one or more harbors where ships can dock and transfer people or cargo to or from land....
town of Sibolga
Sibolga
Sibolga is a city and a port on the west coast of North Sumatra province, in Indonesia. It is located on the western side of North Sumatra, facing the Indian Ocean and is a transit harbour to Nias island. It was hard hit during the 2004 Indian Ocean Earthquake.- History :Poncan Ketek Island in...
constituting the lower extreme and Mount Pangulubao
Mount Pangulubao
Mount Pangulubao or Pangulubau is a mountain near Lake Toba in Sumatra.Mount Pangulubao is notable for the relatively large number of tropical pitcher plant species that inhabit its forests. These include Nepenthes ampullaria, Nepenthes gymnamphora, Nepenthes mikei, Nepenthes ovata, Nepenthes...
the upper extreme. However, according to 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,...
, N. tobaica can grow as high as 2750 m.
Leptospermum
Leptospermum is a genus of about 80-86 species of plants in the myrtle family Myrtaceae. Most species are endemic to Australia, with the greatest diversity in the south of the continent; but one species extends to New Zealand, another to Malaysia, and L. recurvum is endemic to Malaysia.They...
and Rhodomyrtus
Rhodomyrtus
Rhodomyrtus is a genus of 24 species of shrubs and trees in the family Myrtaceae. The genus is native to Asia, Malesia, Melanesia, and Australia. Its greatest levels of diversity are on New Guinea and in northeastern Australia. DNA sequence data and morphological data indicate that the genus is...
.
Nepenthes tobaica is very abundant in the Lake Toba
Lake Toba
Lake Toba is a lake and supervolcano. The lake is 100 kilometres long and 30 kilometres wide, and 505 metres at its deepest point. Located in the middle of the northern part of the Indonesian island of Sumatra with a surface elevation of about , the lake stretches from to...
region, to the point where it is "difficult to avoid seeing it there". N. tobaica is also known to grow in high altitude peat swamp forest near Lake Kerinci
Lake Kerinci
Lake Kerinci is a lake in Jambi, Indonesia. It is located at ....
, at an altitude of 1100 m. At this location, the species grows alongside N. ampullaria
Nepenthes ampullaria
Nepenthes ampullaria , the Flask-Shaped Pitcher-Plant, is a very distinctive and widespread species of Nepenthes, present in Borneo, Sumatra, Thailand, Peninsular Malaysia, Singapore, the Maluku Islands, and New Guinea...
, N. gracilis
Nepenthes gracilis
Nepenthes gracilis , or the Slender Pitcher-Plant, is a very common lowland pitcher plant that is widespread in the Sunda region. It has been recorded from Borneo, Peninsular Malaysia, Singapore, central Sulawesi, Sumatra, and southernmost Thailand...
, N. mirabilis
Nepenthes mirabilis
Nepenthes mirabilis , or the Common Swamp Pitcher-Plant, is a tropical carnivorous plant species of the pitfall trap variety. It has by far the widest distribution of any Nepenthes species and is known from the following countries and regions: Borneo, Sumatra, Thailand, Peninsular Malaysia,...
, N. reinwardtiana
Nepenthes reinwardtiana
Nepenthes reinwardtiana , Reinwardt's Pitcher-Plant, is a Nepenthes species found on the islands of Borneo and Sumatra. Although some sources have included Peninsular Malaysia and Singapore within the range of this species, these records appear to be erroneous.Nepenthes reinwardtiana has an...
, and N. spathulata
Nepenthes spathulata
Nepenthes spathulata is a tropical pitcher plant native to Java and Sumatra, where it grows at elevations of between 1100 and 2900 m above sea level. The specific epithet spathulata is derived from the Latin word spathulatus, meaning "spatula shaped", and refers to the shape of the...
. The Nepenthes species and hybrids at this site exhibit high levels of introgression
Introgression
Introgression, also known as introgressive hybridization, in genetics is the movement of a gene from one species into the gene pool of another by the repeated backcrossing of an interspecific hybrid with one of its parent species...
. The vegetation is dominated by species of the genera Rhododendron
Rhododendron
Rhododendron is a genus of over 1 000 species of woody plants in the heath family, most with showy flowers...
and Melastoma
Melastoma
Melastoma is a genus in the family Melastomataceae. It has about 50 species distributed around Southeast Asia, India, and Australia. It is undergoing taxonomic revision. Many species have been planted around the world for the aesthetic value of their bright purple flowers...
, as well as orchids and fern
Fern
A fern is any one of a group of about 12,000 species of plants belonging to the botanical group known as Pteridophyta. Unlike mosses, they have xylem and phloem . They have stems, leaves, and roots like other vascular plants...
s. It is very stunted and dense, with few trees exceeding 3 m in height. It is somewhat reminiscent of the highland 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:**...
s around Bareo
Bareo
Bareo is a small village situated on the National Highway-31. It shares schools with Namdargunj as other nearby villages in this area. The population consists of both Hindus and Muslims....
in 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...
, 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 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. tobaica is listed as Least Concern
Least Concern
Least Concern is an IUCN category assigned to extant taxon or lower taxa which have been evaluated but do not qualify for any other category. As such they do not qualify as threatened, Near Threatened, or Conservation Dependent...
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.
Pitcher infauna
The pitchers of N. tobaica play host to a wide variety of infaunal organismsNepenthes 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...
.
The mite
Mite
Mites, along with ticks, are small arthropods belonging to the subclass Acari and the class Arachnida. The scientific discipline devoted to the study of ticks and mites is called acarology.-Diversity and systematics:...
species Creutzeria tobaica was described from the pitchers of a Java
Java
Java is an island of Indonesia. With a population of 135 million , it is the world's most populous island, and one of the most densely populated regions in the world. It is home to 60% of Indonesia's population. The Indonesian capital city, Jakarta, is in west Java...
nese Nepenthes identified as N. tobaica. However, N. tobaica has not been recorded outside of Sumatra.
Related species
| Character | N. angasanensis | N. mikei | N. tobaica |
|---|---|---|---|
| Habit | Produces offshoots from underground rhizomes | No rhizomes | No rhizomes |
| Spur | Forked | Fasciculate | Filiform |
| Inner margin of peristome | Teeth to 1.5–2 mm long | Teeth to 0.2-0.4 mm long | Teeth < 0.2 mm |
| Stem cross section | Cylindrical | Cylindrical | Cylindrical to obtusely triangular |
| Bracteoles | Sometimes near base of lowest pedicel only | Half way up every pedicel | At base or slightly below pedicel attachment, few |
| Pitcher glands | 300 / cm² | 150-180 / cm² | 200-250 / cm² |
| Pedicels | 1-flowered | 1-flowered | 2-flowered |
| Inflorescence (female) | 55–125 mm long, 9-17 flowers | 40–80 mm long, 4-10 flowers | 195–400 mm long, 30-50 flowers |
In 2001, Charles Clarke
Charles Clarke (botanist)
Dr. Charles M. Clarke is a botanist and taxonomist specialising in the carnivorous plant genus Nepenthes. Clarke has an honours degree in Botany from Monash University in Melbourne, and a Ph.D. in Ecosystem Management at the University of New England, in Armidale, New South Wales.Clarke first...
performed a cladistic analysis of the Nepenthes species of Sumatra and Peninsular Malaysia
Peninsular Malaysia
Peninsular Malaysia , also known as West Malaysia , is the part of Malaysia which lies on the Malay Peninsula. Its area is . It shares a land border with Thailand in the north. To the south is the island of Singapore. Across the Strait of Malacca to the west lies the island of Sumatra...
using 70 morphological characteristics of each taxon. The following is a portion of the resultant cladogram
Cladogram
A cladogram is a diagram used in cladistics which shows ancestral relations between organisms, to represent the evolutionary tree of life. Although traditionally such cladograms were generated largely on the basis of morphological characters, DNA and RNA sequencing data and computational...
, showing part of "Clade 6". The sister pair of N. angasanensis and N. mikei has 79% support.
Nepenthes adnata
Nepenthes adnata is a tropical pitcher plant endemic to the Indonesian province of West Sumatra, where it grows at elevations of 600 to 1200 m above sea level. The specific epithet adnata is Latin for "broadly attached" and refers to the base of the lamina.-Botanical history:Nepenthes adnata was...
, although the stem and lamina are quite different.
Natural hybrids
Five natural hybrids involving N. tobaica have been recorded to date; specifically, crosses with N. ampullariaNepenthes ampullaria
Nepenthes ampullaria , the Flask-Shaped Pitcher-Plant, is a very distinctive and widespread species of Nepenthes, present in Borneo, Sumatra, Thailand, Peninsular Malaysia, Singapore, the Maluku Islands, and New Guinea...
, N. reinwardtiana
Nepenthes reinwardtiana
Nepenthes reinwardtiana , Reinwardt's Pitcher-Plant, is a Nepenthes species found on the islands of Borneo and Sumatra. Although some sources have included Peninsular Malaysia and Singapore within the range of this species, these records appear to be erroneous.Nepenthes reinwardtiana has an...
, N. rhombicaulis
Nepenthes rhombicaulis
Nepenthes rhombicaulis is a tropical pitcher plant endemic to Sumatra. The specific epithet rhombicaulis is formed from the Latin words rhombicus, meaning "rhomboid", and caulis, "stem"...
, N. spathulata
Nepenthes spathulata
Nepenthes spathulata is a tropical pitcher plant native to Java and Sumatra, where it grows at elevations of between 1100 and 2900 m above sea level. The specific epithet spathulata is derived from the Latin word spathulatus, meaning "spatula shaped", and refers to the shape of the...
, and N. spectabilis
Nepenthes spectabilis
Nepenthes spectabilis is a tropical pitcher plant endemic to Sumatra, where it grows at elevations of between 1400 and 2200 m above sea level. The specific epithet spectabilis is Latin for "visible" or "notable".-Botanical history:...
.
External links
- Nepenthes tobaica at NPGS/GRINGermplasm Resources Information NetworkGermplasm Resources Information Network or GRIN is an online software project of National Genetic Resources Program of USDA to provide germplasm information about plants, animals, microbes and invertebrates.-Sub-Projects:...