Nepenthes mikei
Encyclopedia
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
.
The specific epithet mikei honours Mike Hopkins, who co-discovered the species with the describing authors.
in September 1989 by Bruce Salmon, Mike Hopkins, and Ricky Maulder, during a Nepenthes expedition to Sumatra
. On this trip, the team also found two other undescribed Nepenthes taxa
on the mountain: N. ovata
and a plant they named N. xiphioides. The latter is now considered a heterotypic synonym of N. gymnamphora
.
An early colour photograph of N. mikei was published by Mike Hopkins, Ricky Maulder, and Bruce Salmon, in a 1990 issue of the Carnivorous Plant Newsletter
, where the plant was identified simply as Nepenthes sp. 'New Species'. The authors described it as follows:
Prior to its description, N. mikei was known as N. minutissima among pitcher plant growers. This name is a nomen nudum
(naked name), as it was never formally published.
Nepenthes mikei was formally described
by Bruce Salmon and Ricky Maulder in a 1995 issue of the Carnivorous Plant Newsletter. The herbarium
specimen B.Salmon & R.Maulder 221719 is the designated holotype
, and is deposited at the Auckland Institute and Museum (AK) in Auckland
, New Zealand
. It was prepared on February 17, 1995, from a plant cultivated in New Zealand
, and consists of a vine bearing a female
inflorescence
, a lower pitcher, and a rosette
. The specimen was originally collected in 1989 from a "very steep ridge in wet mossy forest" near the summit of Mount Pangulubao
, at an altitude of 2000 m. The authors described the plant as growing "in peat
y humus or moss at the base of 5–6 m tall trees". Salmon and Maulder also pressed a second specimen of N. mikei from material collected at the same elevation on Pangulubao. Additional herbarium specimens of N. mikei are known and these show slight morphological variability.
In 1997, Matthew Jebb
and Martin Cheek
published their monograph "A skeletal revision of Nepenthes (Nepenthaceae)
", in which they provided an emended description of N. mikei that encompassed specimens of the closely related, and at the time undescribed, N. angasanensis
from Mount Leuser
, Goh Lembuh, and the Kappi region. Salmon and Maulder did not support this interpretation and reinstated their original description of N. mikei when they described N. angasanensis in 1999. Jebb and Cheek retained N. angasanensis as a synonym of N. mikei in their 2001 monograph, "Nepenthaceae
", writing: "We suspect that it [N. angasanensis] may prove not distinct from N. mikei and here treat it as a synonym."
, which may be branched, is up to 0.4 cm in diameter and has cylindrical to angular internodes measuring up to 9 cm in length. Plants from Mount Bandahara are known to produce offshoots from short underground rhizome
s. Nepenthes mikei is noted for rapidly transitioning from a rosette
to a climbing stage; sequential internodal lengths of 2–3 mm and 10 cm have been recorded.
Leaves are sessile and coriaceous in texture. The lamina (leaf blade) is linear and measures up to 10 cm in length by 2 cm in width. Its apex may be acute or obtuse and it is abruptly contracted at the base, clasping the stem for around half of its circumference. One to two longitudinal veins are present on either side of the midrib, while pinnate veins are irregularly reticulate. The upper surface of the lamina is typically green, but may be red if exposed to direct sunlight. Tendril
s are up to 15 cm long.
Rosette and lower pitchers are ovate in the basal third to quarter of the pitcher cup, becoming approximately cylindrical above and infundibular towards the pitcher mouth. They are relatively small, growing to only 12 cm in height by 3 cm in width. A pair of wings (≤4 mm wide) typically runs down the ventral surface of the pitcher cup, with fringe elements measuring up to 8 mm in length. These wings may be reduced to ribs in some plants. The gland
ular region on the inner surface is restricted to the ovate portion of the pitcher cup. The glands are small (0.2–0.3 mm in diameter) and occur at a density of around 150–180 per square centimetre. Eye spots may occasionally be present on the rear inner surface, visible through the opening. The peristome
is sub-cylindrical to cylindrical and up to 4 mm wide. It bears ribs up to 0.1 mm high and spaced 0.2 mm apart, which terminate in teeth up to 0.4 mm long. The pitcher lid or operculum
is ovate and has a cordate base. It measures up to 3 cm in length by 2.5 cm in width and does not bear any appendages. The underside of the lid has an even distribution of small (0.1–0.2 mm in diameter) convex glands, occurring at a density of about 40/cm2. The spur, which is inserted near the base of the lid, is up to 7 mm long and may be simple, forked, or fasciculate with up to 12 branches.
Upper pitchers are ovate in their basal third to fifth, becoming cylindrical above and infundibular towards the peristome. They are smaller than their lower counterparts, reaching only 8 cm in height by 2 cm in width. Wings are always reduced to ribs. In other respects, upper pitchers are similar to the lower traps.
Nepenthes mikei has a racemose
inflorescence
measuring up to 18 cm in length by 1.8 cm in diameter. The peduncle
itself may be up to 8 cm long by 1 mm wide in female plants, and up to 3 cm long in males. The rachis
is up to 8 cm long. The inflorescence bears one-flowered pedicels
(≤6 mm long), which may be bracteoleate. The oblong-lanceolate tepal
s measure up to 4 mm in length. Fruit
s are up to 22 mm long.
Most parts of the plant are glabrous. An indumentum
of short, white or yellowish hairs is usually present on the tendrils and some parts of the inflorescence. This indumentum is a mixture of simple and stellate hairs. Caducous hairs cover developing pitchers and other parts.
n island of Sumatra
, where it has been recorded from only two mountains: Mount Pangulubao
in North Sumatra
and Mount Bandahara in Aceh
. Its altitudinal distribution extends from 1100–2800 m.
The typical habitat of this species is summit scrub
vegetation as well as lower and upper montane mossy forest. It always grows terrestrially, often in open sites such as ridge tops and cliff sides, where it is exposed to direct sunlight. The species is rare in blangs, where the lack of surrounding vegetation means the stems scramble along the ground. Nepenthes mikei may be difficult to find on Mount Pangulubao, where it is sympatric
with N. gymnamphora
(N. xiphioides), N. ovata
, and N. spectabilis
. On Mount Bandahara, where it is common above 2400 m, it grows alongside N. diatas
. Natural hybrids with all of these species have been recorded. At another location, which is undisclosed for conservation purposes, N. mikei grows alongside N. flava
.
The conservation status
of N. mikei is listed as Vulnerable
on the IUCN Red List
, based on an assessment carried out in 2000. This agrees with an informal assessment made by Charles Clarke
in 2001, who also classified the species as Vulnerable based on the IUCN
criteria. However, Clarke noted that since substantial populations of N. mikei lie within protected areas, they "are unlikely to become threatened in the foreseeable future". Taking this into account, he suggested a revised assessment of Conservation Dependent
. The species is threatened by habitat loss and disturbance, as well as over-collection by plant collectors.
n endemics N. angasanensis
and N. tobaica
, and may be conspecific with the former.
In their description of N. mikei, Salmon and Maulder noted many differences between it and N. angasanensis which are now known to be unreliable. For example, the authors wrote that N. angasanensis produces offshoots from underground rhizome
s, while N. mikei does not; populations of N. mikei from Mount Bandahara are now known to produce such offshoots. Similarly, N. angasanensis was said to lack a fasciculate spur, but this has since been recorded in lower pitchers of this species. Disregarding these supposed differences leaves only a few stable distinguishing features between the species. Firstly, the teeth lining the inner margin of the peristome
are shorter in N. mikei, although both have minute teeth and this difference is minor. Secondly, the pedicels
of N. mikei bear simple bract
eoles, while those of N. angasanensis do not. Finally, N. angasanensis exhibits a greater density of digestive glands on the inner pitcher surface.
Nepenthes angasanensis and N. mikei are more easily distinguished by their differing ecology. While N. angasanensis is generally found growing terrestrially or epiphytically
in shady mossy forest, N. mikei is always terrestrial and favours more exposed sites where it receives strong sunlight. Nepenthes angasanensis also typically produces longer stems, with regular offshoots from the leaf axils, although these have been observed in N. mikei as well.
Nepenthes tobaica differs from N. mikei in a number of floral and vegetative features. Whereas the latter has a shorter inflorescence
with flowers borne singly on pedicels
, N. tobaica has two-flowered partial peduncles
. In addition, N. tobaica lacks the fasciculate spur of N. mikei and generally has wider laminae.
Salmon and Maulder also compared N. mikei to N. adnata
and N. tentaculata
. Stewart McPherson
noted that the species may also superficially resemble N. eustachya
in the shape of its pitchers.
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.
Clarke concluded that the "relationships between [these species] are very complex and are somewhat difficult to interpret at present".
is restricted to Mount Bandahara and thus this hybrid only occurs on that mountain. This cross is common between 2300 and 2700 m, where the altitudinal ranges of the two species overlap. It was first reported in 1998.
This hybrid is similar to N. mikei and also produces mostly black lower pitchers. It differs in that the terrestrial traps have a wider basal portion. The plant is also larger in stature, having broader stems and leaves, and bears a wider peristome than N. mikei.
Nepenthes diatas × N. mikei has only been found at the forest margins in the summit area of Mount Bandahara. It has not been recorded from the mountain's open blangs.
, N. ovata
, and N. spectabilis
— have been observed. All three were first reported in 1995 by Salmon and Maulder from Mount Pangulubao
. Nepenthes gymnamphora × N. mikei was given the informal name N. × pangulubauensis
in 1996.
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 characterised by its black mottled lower and upper pitchers. The species 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...
and N. tobaica
Nepenthes tobaica
Nepenthes tobaica is a tropical pitcher plant endemic to Sumatra. It is particularly abundant around Lake Toba, after which it is named....
.
The specific epithet mikei honours Mike Hopkins, who co-discovered the species with the describing authors.
Botanical history
Nepenthes mikei was discovered on Mount PangulubaoMount 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...
in September 1989 by Bruce Salmon, Mike Hopkins, and Ricky Maulder, during a Nepenthes expedition 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...
. On this trip, the team also found two other undescribed Nepenthes 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...
on the mountain: N. ovata
Nepenthes ovata
Nepenthes ovata is a tropical pitcher plant endemic to Sumatra. The specific epithet ovata is Latin for "ovate" and refers to the shape of the lower pitchers.-Botanical history:...
and a plant they named N. xiphioides. The latter is now considered a heterotypic synonym of N. gymnamphora
Nepenthes gymnamphora
Nepenthes gymnamphora is a tropical pitcher plant native to the Indonesian islands of Java and Sumatra. There is much debate surrounding the taxonomic status of this species and the taxa N. pectinata and N. xiphioides....
.
An early colour photograph of N. mikei was published by Mike Hopkins, Ricky Maulder, and Bruce Salmon, in a 1990 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:...
, where the plant was identified simply as Nepenthes sp. 'New Species'. The authors described it as follows:
We saw another Nepenthes that is different than the others we saw in the higher highland areas. It has small pitchers slightly similar to N. tentaculataNepenthes tentaculataNepenthes tentaculata , or the Fringed Pitcher-Plant, is a tropical pitcher plant with a very wide distribution across Borneo and Sulawesi...
, N. tobaicaNepenthes tobaicaNepenthes tobaica is a tropical pitcher plant endemic to Sumatra. It is particularly abundant around Lake Toba, after which it is named....
and N. gracilisNepenthes gracilisNepenthes 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...
but tougher and thicker. The pitchers are always nicely colored with blackish lines and markings similar to N. fuscaNepenthes fuscaNepenthes 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....
. There was very little variation with this species as all mature plants had ample rosettesRosette (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:...
on the ground and also at intervals up the stem. The stems were slimbing up to about 7 meters and had upper pitchers similar in color and shape to the lower pitchers but with the usual differences. The male inflorescences were about 20 centimeters, peduncle inclusive.
Prior to its description, N. mikei was known as N. minutissima among pitcher plant growers. This name is a nomen nudum
Nomen nudum
The phrase nomen nudum is a Latin term, meaning "naked name", used in taxonomy...
(naked name), as it was never formally published.
Nepenthes mikei 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 Bruce Salmon and Ricky Maulder in a 1995 issue of the Carnivorous Plant Newsletter. 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...
specimen B.Salmon & R.Maulder 221719 is the designated 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...
, and is deposited at the Auckland Institute and Museum (AK) in Auckland
Auckland
The Auckland metropolitan area , in the North Island of New Zealand, is the largest and most populous urban area in the country with residents, percent of the country's population. Auckland also has the largest Polynesian population of any city in the world...
, New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
. It was prepared on February 17, 1995, from a plant cultivated in New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
, and consists of a vine bearing a female
Female
Female is the sex of an organism, or a part of an organism, which produces non-mobile ova .- Defining characteristics :The ova are defined as the larger gametes in a heterogamous reproduction system, while the smaller, usually motile gamete, the spermatozoon, is produced by the male...
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...
, a lower pitcher, and a 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:...
. The specimen was originally collected in 1989 from a "very steep ridge in wet mossy forest" near the summit of 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...
, at an altitude of 2000 m. The authors described the plant as growing "in peat
Peat
Peat is an accumulation of partially decayed vegetation matter or histosol. Peat forms in wetland bogs, moors, muskegs, pocosins, mires, and peat swamp forests. Peat is harvested as an important source of fuel in certain parts of the world...
y humus or moss at the base of 5–6 m tall trees". Salmon and Maulder also pressed a second specimen of N. mikei from material collected at the same elevation on Pangulubao. Additional herbarium specimens of N. mikei are known and these show slight morphological variability.
In 1997, 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,...
published their monograph "A skeletal revision of Nepenthes (Nepenthaceae)
A skeletal revision of Nepenthes (Nepenthaceae)
"A skeletal revision of Nepenthes " is a monograph by Matthew Jebb and Martin Cheek on the tropical pitcher plants of the genus Nepenthes. It was published in the May 1997 issue of the botanical journal Blumea. The work represented the first revision of the entire genus since John Muirhead...
", in which they provided an emended description of N. mikei that encompassed specimens of the closely related, and at the time undescribed, 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...
from Mount Leuser
Mount Leuser
Mount Leuser is the tallest mountain in the Indonesian province of Aceh, with an elevation of .The Gunung Leuser National Park protects the mountain and its surrounding ecosystems. It has been confirmed by some scientists that 2004 Indian Ocean earthquake has activated the volcano...
, Goh Lembuh, and the Kappi region. Salmon and Maulder did not support this interpretation and reinstated their original description of N. mikei when they described N. angasanensis in 1999. Jebb and Cheek retained N. angasanensis as a synonym of N. mikei in their 2001 monograph, "Nepenthaceae
Nepenthaceae (2001 monograph)
"Nepenthaceae" is a monograph by Martin Cheek and Matthew Jebb on the tropical pitcher plants of Malesia, which encompasses Brunei, Indonesia, Malaysia, Papua New Guinea, the Philippines, and Singapore. It was published in 2001 by the National Herbarium of the Netherlands as the fifteenth volume of...
", writing: "We suspect that it [N. angasanensis] may prove not distinct from N. mikei and here treat it as a synonym."
Description
Nepenthes mikei is a climbing plant growing to a height of 7 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...
, which may be branched, is up to 0.4 cm in diameter and has cylindrical to angular internodes measuring up to 9 cm in length. Plants from Mount Bandahara are known to produce offshoots from short underground rhizome
Rhizome
In botany and dendrology, a rhizome is a characteristically horizontal stem of a plant that is usually found underground, often sending out roots and shoots from its nodes...
s. Nepenthes mikei is noted for rapidly transitioning from a 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:...
to a climbing stage; sequential internodal lengths of 2–3 mm and 10 cm have been recorded.
Leaves are sessile and coriaceous in texture. The lamina (leaf blade) is linear and measures up to 10 cm in length by 2 cm in width. Its apex may be acute or obtuse and it is abruptly contracted at the base, clasping the stem for around half of its circumference. One to two longitudinal veins are present on either side of the midrib, while pinnate veins are irregularly reticulate. The upper surface of the lamina is typically green, but may be red if exposed to direct sunlight. 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 up to 15 cm long.
Rosette and lower pitchers are ovate in the basal third to quarter of the pitcher cup, becoming approximately cylindrical above and infundibular towards the pitcher mouth. They are relatively small, growing to only 12 cm in height by 3 cm in width. A pair of wings (≤4 mm wide) typically runs down the ventral surface of the pitcher cup, with fringe elements measuring up to 8 mm in length. These wings may be reduced to ribs in some plants. 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 on the inner surface is restricted to the ovate portion of the pitcher cup. The glands are small (0.2–0.3 mm in diameter) and occur at a density of around 150–180 per square centimetre. Eye spots may occasionally be present on the rear inner surface, visible through the opening. 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 sub-cylindrical to cylindrical and up to 4 mm wide. It bears ribs up to 0.1 mm high and spaced 0.2 mm apart, which terminate in teeth up to 0.4 mm long. 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 and has a cordate base. It measures up to 3 cm in length by 2.5 cm in width and does not bear any appendages. The underside of the lid has an even distribution of small (0.1–0.2 mm in diameter) convex glands, occurring at a density of about 40/cm2. The spur, which is inserted near the base of the lid, is up to 7 mm long and may be simple, forked, or fasciculate with up to 12 branches.
Upper pitchers are ovate in their basal third to fifth, becoming cylindrical above and infundibular towards the peristome. They are smaller than their lower counterparts, reaching only 8 cm in height by 2 cm in width. Wings are always reduced to ribs. In other respects, upper pitchers are similar to the lower traps.
Nepenthes mikei 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...
measuring up to 18 cm in length by 1.8 cm in diameter. 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...
itself may be up to 8 cm long by 1 mm wide in female plants, and up to 3 cm long in males. The 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...
is up to 8 cm long. The inflorescence bears one-flowered 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....
(≤6 mm long), which may be bracteoleate. The oblong-lanceolate tepal
Tepal
Tepals are elements of the perianth, or outer part of a flower, which include the petals or sepals. The term tepal is more often applied specifically when all segments of the perianth are of similar shape and color, or undifferentiated, which is called perigone...
s measure up to 4 mm in length. Fruit
Fruit
In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...
s are up to 22 mm long.
Most parts of the plant are glabrous. An 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, white or yellowish hairs is usually present on the tendrils and some parts of the inflorescence. This indumentum is a mixture of simple and stellate hairs. Caducous hairs cover developing pitchers and other parts.
Ecology
Nepenthes mikei is endemic to the IndonesiaIndonesia
Indonesia , officially the Republic of Indonesia , is a country in Southeast Asia and Oceania. Indonesia is an archipelago comprising approximately 13,000 islands. It has 33 provinces with over 238 million people, and is the world's fourth most populous country. Indonesia is a republic, with an...
n island of Sumatra
Sumatra
Sumatra is an island in western Indonesia, westernmost of the Sunda Islands. It is the largest island entirely in Indonesia , and the sixth largest island in the world at 473,481 km2 with a population of 50,365,538...
, where it has been recorded from only two mountains: 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...
in North Sumatra
North Sumatra
North Sumatra is a province of Indonesia on the Sumatra island. Its capital is Medan. It is the most populous Indonesian province outside of Java. It is slightly larger than Sri Lanka in area.- Geography and population :...
and Mount Bandahara in 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...
. Its altitudinal distribution extends from 1100–2800 m.
The typical habitat of this species is summit scrub
Shrubland
Shrubland, scrubland, scrub or brush is a plant community characterized by vegetation dominated by shrubs, often also including grasses, herbs, and geophytes. Shrubland may either occur naturally or be the result of human activity...
vegetation as well as lower and upper montane mossy forest. It always grows terrestrially, often in open sites such as ridge tops and cliff sides, where it is exposed to direct sunlight. The species is rare in blangs, where the lack of surrounding vegetation means the stems scramble along the ground. Nepenthes mikei may be difficult to find on Mount Pangulubao, where it 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. gymnamphora
Nepenthes gymnamphora
Nepenthes gymnamphora is a tropical pitcher plant native to the Indonesian islands of Java and Sumatra. There is much debate surrounding the taxonomic status of this species and the taxa N. pectinata and N. xiphioides....
(N. xiphioides), N. ovata
Nepenthes ovata
Nepenthes ovata is a tropical pitcher plant endemic to Sumatra. The specific epithet ovata is Latin for "ovate" and refers to the shape of the lower pitchers.-Botanical history:...
, 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:...
. On Mount Bandahara, where it is common above 2400 m, it grows alongside N. diatas
Nepenthes diatas
Nepenthes diatas is a tropical pitcher plant endemic to Sumatra, where it grows at an altitude of between 2400 and 2900 m above sea level....
. Natural hybrids with all of these species have been recorded. At another location, which is undisclosed for conservation purposes, N. mikei grows alongside N. flava
Nepenthes flava
Nepenthes flava is a tropical pitcher plant endemic to northern Sumatra, where it grows in montane forest at 1800–2200 m above sea level....
.
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. mikei is listed 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:...
on the IUCN Red List
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. This agrees with an informal assessment made by 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...
in 2001, who also classified the species as Vulnerable based on the IUCN
World Conservation Union
The International Union for Conservation of Nature and Natural Resources is an international organization dedicated to finding "pragmatic solutions to our most pressing environment and development challenges." The organization publishes the IUCN Red List, compiling information from a network of...
criteria. However, Clarke noted that since substantial populations of N. mikei lie within protected areas, they "are unlikely to become threatened in the foreseeable future". Taking this into account, he suggested a revised assessment of Conservation Dependent
Conservation Dependent
Conservation Dependent was an IUCN category assigned to species or lower taxa which were dependent on conservation efforts to prevent the taxon becoming threatened with extinction...
. The species is threatened by habitat loss and disturbance, as well as over-collection by plant collectors.
Related species
Nepenthes mikei is most closely allied to the 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...
n endemics 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...
and N. tobaica
Nepenthes tobaica
Nepenthes tobaica is a tropical pitcher plant endemic to Sumatra. It is particularly abundant around Lake Toba, after which it is named....
, and may be conspecific with the former.
In their description of N. mikei, Salmon and Maulder noted many differences between it and N. angasanensis which are now known to be unreliable. For example, the authors wrote that N. angasanensis produces offshoots from underground rhizome
Rhizome
In botany and dendrology, a rhizome is a characteristically horizontal stem of a plant that is usually found underground, often sending out roots and shoots from its nodes...
s, while N. mikei does not; populations of N. mikei from Mount Bandahara are now known to produce such offshoots. Similarly, N. angasanensis was said to lack a fasciculate spur, but this has since been recorded in lower pitchers of this species. Disregarding these supposed differences leaves only a few stable distinguishing features between the species. Firstly, the teeth lining the inner margin of 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...
are shorter in N. mikei, although both have minute teeth and this difference is minor. Secondly, the 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....
of N. mikei bear simple bract
Bract
In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis, or cone scale. Bracts are often different from foliage leaves. They may be smaller, larger, or of a different color, shape, or texture...
eoles, while those of N. angasanensis do not. Finally, N. angasanensis exhibits a greater density of digestive glands on the inner pitcher surface.
Nepenthes angasanensis and N. mikei are more easily distinguished by their differing ecology. While N. angasanensis is generally found growing terrestrially or epiphytically
Epiphyte
An epiphyte is a plant that grows upon another plant non-parasitically or sometimes upon some other object , derives its moisture and nutrients from the air and rain and sometimes from debris accumulating around it, and is found in the temperate zone and in the...
in shady mossy forest, N. mikei is always terrestrial and favours more exposed sites where it receives strong sunlight. Nepenthes angasanensis also typically produces longer stems, with regular offshoots from the leaf axils, although these have been observed in N. mikei as well.
Nepenthes tobaica differs from N. mikei in a number of floral and vegetative features. Whereas the latter has a shorter 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...
with flowers borne singly on 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....
, N. tobaica has two-flowered 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...
. In addition, N. tobaica lacks the fasciculate spur of N. mikei and generally has wider laminae.
Salmon and Maulder also compared N. mikei to N. adnata
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...
and N. tentaculata
Nepenthes tentaculata
Nepenthes tentaculata , or the Fringed Pitcher-Plant, is a tropical pitcher plant with a very wide distribution across Borneo and Sulawesi...
. 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....
noted that the species may also superficially resemble N. eustachya
Nepenthes eustachya
Nepenthes eustachya is a tropical pitcher plant endemic to Sumatra, where it grows from sea level to an elevation of 1600 m. The specific epithet eustachya, formed from the Greek words eu and stachys , refers to the racemose structure of the inflorescence.-Botanical history:Nepenthes eustachya...
in the shape of its pitchers.
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.
Clarke concluded that the "relationships between [these species] are very complex and are somewhat difficult to interpret at present".
Natural hybrids
Four natural hybrids involving N. mikei have been recorded.N. diatas × N. mikei
Nepenthes diatasNepenthes diatas
Nepenthes diatas is a tropical pitcher plant endemic to Sumatra, where it grows at an altitude of between 2400 and 2900 m above sea level....
is restricted to Mount Bandahara and thus this hybrid only occurs on that mountain. This cross is common between 2300 and 2700 m, where the altitudinal ranges of the two species overlap. It was first reported in 1998.
This hybrid is similar to N. mikei and also produces mostly black lower pitchers. It differs in that the terrestrial traps have a wider basal portion. The plant is also larger in stature, having broader stems and leaves, and bears a wider peristome than N. mikei.
Nepenthes diatas × N. mikei has only been found at the forest margins in the summit area of Mount Bandahara. It has not been recorded from the mountain's open blangs.
Other hybrids
Three other natural hybrids — with N. gymnamphoraNepenthes gymnamphora
Nepenthes gymnamphora is a tropical pitcher plant native to the Indonesian islands of Java and Sumatra. There is much debate surrounding the taxonomic status of this species and the taxa N. pectinata and N. xiphioides....
, N. ovata
Nepenthes ovata
Nepenthes ovata is a tropical pitcher plant endemic to Sumatra. The specific epithet ovata is Latin for "ovate" and refers to the shape of the lower pitchers.-Botanical history:...
, 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:...
— have been observed. All three were first reported in 1995 by Salmon and Maulder from 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...
. Nepenthes gymnamphora × N. mikei was given the informal name N. × pangulubauensis
Nepenthes × pangulubauensis
Nepenthes × pangulubauensis is a natural hybrid between N. mikei and N. gymnamphora . It is endemic to the Indonesian island of Sumatra.-References:*...
in 1996.
External links
- Photographs of N. mikei at the Carnivorous Plant Photofinder