Nepenthes edwardsiana
Encyclopedia
Nepenthes edwardsiana or the Splendid Pitcher-Plant, is a tropical pitcher plant
endemic to Mount Kinabalu
and neighbouring Mount Tambuyukon
in Sabah
, Malaysian Borneo. It is considered one of the most spectacular of all Nepenthes
, producing some of the largest pitchers and the most highly developed peristome
ribs of any species in the genus
.
in 1858 by a climbing team consisting of Hugh Low
, Frederick William Burbidge
, and Spenser St. John. Designated as Low s.n., the specimen is deposited at the Royal Botanic Gardens, Kew
.
Nepenthes edwardsiana was formally described
in 1859 by Joseph Dalton Hooker
. Hooker named the species after George Edwards, Governor of the Crown Colony of Labuan, at the request of his friend Hugh Low
. Hooker's original description and illustration were reproduced in Spenser St. John's Life in the Forests of the Far East, published in 1862. St. John wrote the following account of N. edwardsiana on Mount Kinabalu:
Alfred Russel Wallace
made brief mention of N. edwardsiana in his famous work The Malay Archipelago
, first published in 1869: "Another, Nepenthes Edwardsiania, has a narrow pitcher twenty inches long; while the plant itself grows to a length of twenty feet".
In subsequent years, N. edwardsiana was featured in a number of publications by eminent botanists such as Friedrich Anton Wilhelm Miquel
(1870), Joseph Dalton Hooker
(1873), Frederick William Burbidge
(1882, 1897), Odoardo Beccari
(1886), William E. Dixon (1888), Ernst Wunschmann (1891), Otto Stapf
(1894), Harry James Veitch
(1897), Jacob Gijsbert Boerlage (1900), William Botting Hemsley (1905), and Elmer Drew Merrill
(1921).
However, most of these publications made only passing mention of N. edwardsiana. The first work to include significant taxonomic revisions was that of Günther Beck von Mannagetta und Lerchenau in 1895. Beck was the first to unite N. edwardsiana and N. villosa, making the former a heterotypic synonym of the latter. He also published the name Nepenthes edgeworthii based on a specimen collected in Borneo by Heinrich Gustav Reichenbach
. The specimen, Herb.Reichenbach s.n., is deposited at the University of Vienna
herbarium
(WU). Beck, like all subsequent authors, considered N. edgeworthii to be conspecific with N. edwardsiana.
Nepenthes edwardsiana was formally reinstated as a valid species in John Muirhead Macfarlane
's 1908 monograph, which included a revised description and illustration of the species. Macfarlane also wrote about N. edwardsiana in the Journal of the Linnean Society in 1914 and The Standard Cyclopedia of Horticulture in 1919.
B. H. Danser
treated N. edwardsiana in synonymy with N. villosa in his seminal monograph "The Nepenthaceae of the Netherlands Indies
", published in 1928. The work included a revised Latin
diagnosis and botanical description of N. villosa. Eight years later, Hermann Harms
once again elevated N. edwardsiana to species status. This treatment was supported by Shigeo Kurata
in 1976 and has not been challenged since.
A similar taxon
from Mount Trus Madi
was long considered to be N. edwardsiana. It was described in 1987 as N. edwardsiana subsp.
macrophylla by Johannes Marabini. A decade later, Matthew Jebb
and Martin Cheek
recognised it as a separate species (N. macrophylla
) in their monograph on the genus. This interpretation has been followed by subsequent authors.
s are up to 35 cm long and circular in cross section.
Leaves are coriaceous and petiolate. The lamina is truly lanceolate in shape and may be up to 30 cm long by 7 cm wide. It has an acute-obtuse apex that is occasionally acuminate. The base of the lamina is gradually or abruptly contracted at the petiole
. The petiole is canaliculate and up to 15 cm long. It is generally winged and bears a partly amplexicaul sheath that clasps the stem for two-thirds to three-quarters of its circumference. One to three longitudinal veins are present on either side of the midrib. Pinnate veins are indistinct. Tendril
s are generally between one and two times as long as the lamina and grow to 35 cm in length.
The pitcher base is bulbous to ovoid, with the pitcher cup becoming cylindrical in the upper two-thirds to three-quarters. The pitchers are some of the largest in the genus, sometimes exceeding 50 cm in height and 15 cm in width, although they are usually around 30 cm high. Wings at the front of the pitcher cup are either greatly reduced or absent altogether. On the inner surface of the pitcher, the gland
ular region is present in the bulbous portion. The mouth is elongated into a neck and has an oblique insertion. The peristome
is cylindrical and up to 30 mm wide. It bears very highly developed teeth and ribs, the latter reaching 20 mm in diameter. The pitcher lid or operculum
is cordate, up to 8 cm wide, and lacks appendages. An unbranched spur
up to 20 mm long is inserted near the base of the lid. Pitchers range in colour from light yellow to dark red. The inner surface of the pitcher is usually white, contrasting sharply with the rich colouration of the outer surface. Most parts of the pitcher are very flexible, including the peristome ribs, with only the pitcher base, where the digestive zone is located, being rigid.
Nepenthes edwardsiana has a racemose
inflorescence
. The peduncle
may be up to 30 cm long, whereas the attenuate rachis
reaches 20 cm in length. Pedicels
are one-flowered, up to 25 mm long, and do not possess a bract
. Sepal
s are round to elliptic in shape and up to 5 mm long. A study of 100 pollen
samples taken from a herbarium specimen (Sands 3651, collected at an altitude of 2600 m) found the mean pollen diameter to be 34.4 μm
(SE
= 0.5; CV
= 7.7%).
Most parts of the plant bear an indumentum
of very short hairs, although it is not conspicuous.
Nepenthes edwardsiana varies relatively little across its range; consequently, no infraspecific taxa have been described.
and the eastern side of neighbouring Mount Tambuyukon
in Sabah
, Borneo
. On Mount Kinabalu, this species has been recorded from the Marai Parai
plateau
, East Ridge, Upper Kolopis River
, and an area below the Kambarangoh Telekom station (below Pondok Lowii). Nepenthes edwardsiana has an altitudinal distribution of 1500–2700 m above sea level.
Anthea Phillipps
and Anthony Lamb
note that plants growing in the Racemobambos
bamboo
forest on Mount Tambuyukon produce some of the longest and finest pitchers, having a pronounced waist and ranging in colour from pink to reddish-orange. On the Marai Parai
plateau
of Mount Kinabalu, N. edwardsiana grows amongst shrubs up to 5 m high. Pitchers on these plants rarely exceed 30 cm. The species does not grow along the Kinabalu summit trail and so very few visitors to the park manage to see it. A specimen is kept at the "Mountain Garden" near Kinabalu Park Headquarters.
Mount Kinabalu was only formed around 1 million years ago and during the last ice age, around 20,000 to 10,000 years ago, it had an ice cap
on its summit. As such, it appears that N. edwardsiana is a relatively recent species in evolutionary terms.
Contrary to the observations of Frederick William Burbidge
, N. edwardsiana grows not only as an epiphyte
, but also occurs terrestrially on moss-covered rocks. It typically grows amongst ridge-top vegetation in dense mossy forest. The natural habitat of N. edwardsiana is constantly moist as the slopes are often enveloped in clouds. Despite generally occurring epiphytically, N. edwardsiana seems to grow mostly in areas with ultramafic soils, although it has also been recorded from sandstone
substrate
s.
The El Niño climatic phenomenon of 1997 to 1998 had a catastrophic effect on the Nepenthes species of Mount Kinabalu. The dry period that followed severely depleted some natural populations. Forest fires
broke out in 9 locations in Kinabalu Park, covering a total area of 25 square kilometres and generating large amounts of smog
. Hugo Steiner
recalls being unable to find any pitchers of N. edwardsiana during a trip to Kinabalu in March 1999. During the El Niño period, many plants were temporarily transferred to the park nursery. These were later replanted in the "Nepenthes Garden" in Mesilau
. Since then, Ansow Gunsalam has established a nursery close to the Mesilau Lodge at the base of Kinabalu Park to protect the endangered species of that area, including N. edwardsiana.
The conservation status
of N. edwardsiana is listed as Vulnerable
on the 2006 IUCN Red List of Threatened Species
. The species has also been classified as Vulnerable by the World Conservation Monitoring Centre
. However, Charles Clarke
notes that since all known populations of N. edwardsiana lie within the boundaries of Kinabalu National Park
and are inaccessible to collectors, they "are unlikely to become threatened in the foreseeable future". Taking this into account, Clarke suggests a revised assessment of Conservation Dependent
based on the IUCN
criteria.
and N. villosa
. There has been much taxonomic confusion surrounding the status of these three taxa
.
Joseph Dalton Hooker
, who described both N. edwardsiana and N. villosa, noted the similarity between the two species as follows:
Günther Beck von Mannagetta und Lerchenau was the first to treat N. edwardsiana in synonymy with N. villosa when he published his monograph on the genus in 1895.
In his 1908 monograph, John Muirhead Macfarlane
treated the two taxa as distinct species, writing: "Examinatione microscopica probatur, illas species distinctas esse". This was probably based on the scientific view at the time, which held that plants differing anatomically cannot be forms of the same species.
B. H. Danser
united the species "[w]ith some hesitation" under N. villosa in his 1928 monograph "The Nepenthaceae of the Netherlands Indies
". He suggested that N. villosa is a stunted form of N. edwardsiana from higher altitudes, which flowers at a "juvenile stage of development". Danser acknowledged that the indumentum
of N. villosa is more dense than that of N. edwardsiana, but noted that it "is a difference only of degree".
In 1936, Hermann Harms
once again split the two species. In Nepenthes of Mount Kinabalu
, published in 1976, Shigeo Kurata
supported this interpretation based on field observations and reference to the type descriptions.
Nepenthes macrophylla
was originally described in 1987 as a subspecies
of N. edwardsiana by Johannes Marabini. It was later elevated to species status by Matthew Jebb
and Martin Cheek
. This interpretation was supported by Charles Clarke
, who noted that N. edwardsiana and N. villosa "have more in common" than N. edwardsiana and N. macrophylla.
of these species also differs, with N. villosa being densely hirsute throughout and N. edwardsiana having an inconspicuous covering of very short hairs. The two taxa can also be distinguished on the basis of their floral morphology; the pedicels
of N. villosa have a filiform bract
, while those of N. edwardsiana do not.
Additionally, N. edwardsiana and N. villosa differ considerably in their altitudinal distributions. The latter species generally occurs at ultrahighland elevations (2300–3240 m), whereas N. edwardsiana is found between 1500 and 2700 m. Where their altitudinal distributions overlap, they are still identifiable as distinct species.
Nepenthes edwardsiana differs from N. macrophylla in the structure of its peristome. Although highly developed, the peristome ribs and teeth of N. macrophylla are considerably shorter than those of either N. edwardsiana or N. villosa. The pitcher mouth of N. macrophylla is distinctive in that it rises gradually towards the lid, while at the same time not forming a pronounced neck. In addition, the mouth of this species has a much more oblique insertion than its relatives. Nepenthes macrophylla is also distinguished by its broad, ovate lid. The lower pitchers of N. edwardsiana and N. macrophylla are quite similar in shape, although in the latter species the hip is always positioned in the upper portion of the pitcher cup. The upper pitchers of these species are more distinct, with those of N. macrophylla being more ovoid and less elongated. As its name suggests, N. macrophylla has very large leaves and these may be twice as long as those of N. edwardsiana or N. villosa.
Whereas N. edwardsiana and N. villosa are restricted to the Kinabalu area, N. macrophylla is only found near the summit of Mount Trus Madi
.
Botanists Matthew Jebb
and Martin Cheek
suggest that N. edwardsiana is related to N. mira
, a species endemic to Palawan
in the Philippines
.
× N. edwardsiana and N. edwardsiana × N. rajah
have received little attention in the scientific literature, but N. edwardsiana × N. villosa
has been known since the 19th century and was initially described as a separate species, N. harryana.
. Its two parent species are very closely related and so N. × harryana, which is roughly intermediate in form, may be difficult to distinguish from either of them.
It was originally described as a species in 1882 by Frederick William Burbidge
. John Muirhead Macfarlane
was the first to realise its hybrid origin and described it as such in his monograph of 1908. B. H. Danser
wrote that N. × harryana might be a hybrid as Macfarlane suggested, or a form of N. villosa together with N. edwardsiana.
Nepenthes × harryana can be distinguished from N. villosa on the basis of its pitcher morphology. The pitchers of the hybrid are more cylindrical than those of N. villosa, whereas the indumentum
is more dense than that of N. edwardsiana. The hip of the pitcher cup, which is found just below the peristome in N. villosa and in the lower quarter of N. edwardsiana pitchers, is located around the middle of N. × harryana pitchers. However, N. villosa plants from Mount Tambuyukon
are easier to confuse with this hybrid, as they produce pitchers that may be elongated slightly above the hip.
Nepenthes × harryana is known from a ridge above the Upper Kolopis River
and from two locations along the Kinabalu summit trail. Since N edwardsiana does not grow along the summit trail, it cannot be confused with this hybrid there. Burbidge wrote that N. edwardsiana, N. × harryana, and N. villosa "are quite distinct in zone of the mountain".
In 2004, professional horticulturist Robert Sacilotto wrote a summary of measured tolerances of highland Nepenthes species, based on experiments conducted between 1996 and 2001. Out of all of the studied species, N. edwardsiana proved to be the most challenging. Cotyledon
-stage seedlings showed a 100% mortality rate when exposed to the following conditions: relative humidity
constantly over 90%, water droplets present on the leaves, soil conductivity over 45 microsiemens
, and soil pH
above 6. However, several plants grew well in a substrate consisting of 50% perlite
, 30% Sphagnum
moss, 10% peat moss chunks, and 10% fir
bark. A top dressing of live Sphagnum was found to provide a good anchoring point for developing roots. Humidity levels of 65 to 85% appeared to be optimal, although more mature plants over 1 year old were able to tolerate exposure to relative humidity in the range of 90 to 99% for up to three days. The highest growth rate was exhibited by plants that experienced warm days, with temperatures of 21 to 29 °C (69.8 to 84.2 F), and cool nights, with temperatures of 13 to 16 °C (55.4 to 60.8 F). The seedlings grew very slowly during the first 8 months, but their growth rate increased significantly after they reached approximately 2 cm in diameter. The plants were grown under High Pressure Sodium
lamps. Optimal light intensity seemed to be in the region of 7500-9100 lx
(700-850 fc
). Soil with a pH
of 4.8 to 5.4 and conductivity of less than 24 microsiemens produced the best results. Dried fruit fly
larva
e of the species Drosophila melanogaster
were fed to the plants once their pitchers reached around 3 mm in height. As the pitchers increased in size, they were fed with ant
s (Acanthomyops
sp.).
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 Mount Kinabalu
Mount Kinabalu
Mount Kinabalu is a prominent mountain on the island of Borneo in Southeast Asia. It is located in the East Malaysian state of Sabah and is protected as Kinabalu National Park, a World Heritage Site. Kinabalu is the tallest peak in Borneo's Crocker Range and is the tallest mountain in the Malay...
and neighbouring Mount Tambuyukon
Mount Tambuyukon
Mount Tambuyukon or Tamboyukon is Malaysia's third highest mountain at 2,579 m . It lies close to the famous Mount Kinabalu. The mountain supports a wide range of unique flora and fauna, including a number of pitcher plant species of the genus Nepenthes....
in Sabah
Sabah
Sabah is one of 13 member states of Malaysia. It is located on the northern portion of the island of Borneo. It is the second largest state in the country after Sarawak, which it borders on its southwest. It also shares a border with the province of East Kalimantan of Indonesia in the south...
, Malaysian Borneo. It is considered one of the most spectacular of all Nepenthes
Nepenthes
The Nepenthes , popularly known as tropical pitcher plants or monkey cups, are a genus of carnivorous plants in the monotypic family Nepenthaceae. The genus comprises roughly 130 species, numerous natural and many cultivated hybrids...
, producing some of the largest pitchers and the most highly developed 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...
ribs of any species in the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
.
Botanical history
The type specimen of N. edwardsiana was collected on Mount KinabaluMount Kinabalu
Mount Kinabalu is a prominent mountain on the island of Borneo in Southeast Asia. It is located in the East Malaysian state of Sabah and is protected as Kinabalu National Park, a World Heritage Site. Kinabalu is the tallest peak in Borneo's Crocker Range and is the tallest mountain in the Malay...
in 1858 by a climbing team consisting of Hugh Low
Hugh Low
Sir Hugh Low, GCMG was a British colonial administrator and naturalist. After a long residence in various colonial roles in Labuan, he became the first successful British administrator in the Malay Peninsula. His methods became models for future administrators. He made the first documented ascent...
, Frederick William Burbidge
Frederick William Burbidge
Frederick William Thomas Burbidge was a British explorer who collected many rare tropical plants for the famous Veitch Nurseries. Burbidge's first job was as a gardener at Kew Gardens...
, and Spenser St. John. Designated as Low s.n., the specimen is deposited at the Royal Botanic Gardens, Kew
Royal Botanic Gardens, Kew
The Royal Botanic Gardens, Kew, usually referred to as Kew Gardens, is 121 hectares of gardens and botanical glasshouses between Richmond and Kew in southwest London, England. "The Royal Botanic Gardens, Kew" and the brand name "Kew" are also used as umbrella terms for the institution that runs...
.
Nepenthes edwardsiana 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 1859 by Joseph Dalton Hooker
Joseph Dalton Hooker
Sir Joseph Dalton Hooker OM, GCSI, CB, MD, FRS was one of the greatest British botanists and explorers of the 19th century. Hooker was a founder of geographical botany, and Charles Darwin's closest friend...
. Hooker named the species after George Edwards, Governor of the Crown Colony of Labuan, at the request of his friend Hugh Low
Hugh Low
Sir Hugh Low, GCMG was a British colonial administrator and naturalist. After a long residence in various colonial roles in Labuan, he became the first successful British administrator in the Malay Peninsula. His methods became models for future administrators. He made the first documented ascent...
. Hooker's original description and illustration were reproduced in Spenser St. John's Life in the Forests of the Far East, published in 1862. St. John wrote the following account of N. edwardsiana on Mount Kinabalu:
As we ascended, we left the brushwood and entered a tangled jungle, in which few of the trees were large. The spur of the mountain became very narrow, sometimes not much wider than the path, and was greatly encumbered at one part by the twining stems of the Nepenthes Edwardsiana. This handsome plant was not, however, much diffused along the spur, but confined to a space about a quarter of a mile in length, and climbed upon the trees around, with its fine pitchers hanging from all the lower boughs. We measured one plant and it was twenty feet in length, quite smooth, and the leaves of a very acute shape at both ends. It is a long, cylindrical, finely-frilled pitcher, growing on every leaf; one we picked measured twenty-one inches and a half long, by two and a half in breadth. They swell out a little towards the base, which is bright pea green, the rest of the cylinder being of a brilliant brick-red colour. Its mouth is
nearly circular, the border surrounding it being finely formed of thin plates about a sixth of an inch apart, and about the same in height, and both of a flesh colour; the handsome lid is of a circular shape. The dried specimen forwarded to Dr. Hooker only measured eighteen inches. The plant is epiphytal, growing on
casuarinas (species nova). The pitchers of the young creepers precisely resemble those of the older ones, except in size.
Alfred Russel Wallace
Alfred Russel Wallace
Alfred Russel Wallace, OM, FRS was a British naturalist, explorer, geographer, anthropologist and biologist...
made brief mention of N. edwardsiana in his famous work The Malay Archipelago
The Malay Archipelago
The Malay Archipelago is a book by the British naturalist Alfred Russel Wallace that chronicles his scientific exploration, during the eight year period 1854 to 1862, of the southern portion of the Malay Archipelago including Malaysia, Singapore, the islands of Indonesia, then known as the Dutch...
, first published in 1869: "Another, Nepenthes Edwardsiania, has a narrow pitcher twenty inches long; while the plant itself grows to a length of twenty feet".
In subsequent years, N. edwardsiana was featured in a number of publications by eminent botanists such as Friedrich Anton Wilhelm Miquel
Friedrich Anton Wilhelm Miquel
Friedrich Anton Wilhelm Miquel was a Dutch botanist.He was head of the botanical gardens at Rotterdam , Amsterdam and Utrecht . He directed the Rijksherbarium at Leiden from 1862...
(1870), Joseph Dalton Hooker
Joseph Dalton Hooker
Sir Joseph Dalton Hooker OM, GCSI, CB, MD, FRS was one of the greatest British botanists and explorers of the 19th century. Hooker was a founder of geographical botany, and Charles Darwin's closest friend...
(1873), Frederick William Burbidge
Frederick William Burbidge
Frederick William Thomas Burbidge was a British explorer who collected many rare tropical plants for the famous Veitch Nurseries. Burbidge's first job was as a gardener at Kew Gardens...
(1882, 1897), Odoardo Beccari
Odoardo Beccari
Odoardo Beccari was an Italian naturalist perhaps best known for discovering the titan arum, the plant with the largest unbranched inflorescence in the world, in Sumatra in 1878...
(1886), William E. Dixon (1888), Ernst Wunschmann (1891), Otto Stapf
Otto Stapf
Otto Stapf FRS was an Austrian born botanist and taxonomist.Stapf trained in Vienna, moving to Royal Botanic Gardens, Kew in 1890. He was keeper of the Herbarium from 1909 to 1920...
(1894), Harry James Veitch
Harry Veitch
Sir Harry James Veitch was an eminent English horticulturist in the nineteenth century, who was the head of the family nursery business, James Veitch & Sons, based in Chelsea, London...
(1897), Jacob Gijsbert Boerlage (1900), William Botting Hemsley (1905), and Elmer Drew Merrill
Elmer Drew Merrill
Elmer Drew Merrill was an American botanist, specializing in the flora of the Asia-Pacific region.He was born in East Auburn, Maine, and attended the University of Maine where he received a B.S. in 1898...
(1921).
However, most of these publications made only passing mention of N. edwardsiana. The first work to include significant taxonomic revisions was that of Günther Beck von Mannagetta und Lerchenau in 1895. Beck was the first to unite N. edwardsiana and N. villosa, making the former a heterotypic synonym of the latter. He also published the name Nepenthes edgeworthii based on a specimen collected in Borneo by Heinrich Gustav Reichenbach
Heinrich Gustav Reichenbach
Heinrich Gustav Reichenbach was an ornithologist, botanist and the foremost German orchidologist of the 19th century...
. The specimen, Herb.Reichenbach s.n., is deposited at the University of Vienna
University of Vienna
The University of Vienna is a public university located in Vienna, Austria. It was founded by Duke Rudolph IV in 1365 and is the oldest university in the German-speaking world...
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...
(WU). Beck, like all subsequent authors, considered N. edgeworthii to be conspecific with N. edwardsiana.
Nepenthes edwardsiana was formally reinstated as a valid species in John Muirhead Macfarlane
John Muirhead Macfarlane
John Muirhead Macfarlane was a Scottish botanist. He was born and educated in Scotland, where he occupied several different academic positions at the University of Edinburgh before emigrating to the United States to assume a professorial chair at the University of Pennsylvania in 1893. He held...
's 1908 monograph, which included a revised description and illustration of the species. Macfarlane also wrote about N. edwardsiana in the Journal of the Linnean Society in 1914 and The Standard Cyclopedia of Horticulture in 1919.
B. H. Danser
B. H. Danser
Benedictus Hubertus Danser , often abbreviated B. H. Danser, was a Dutch taxonomist and botanist...
treated N. edwardsiana in synonymy with N. villosa 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...
", published in 1928. The work included a revised 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...
diagnosis and botanical description of N. villosa. Eight years later, Hermann Harms
Hermann Harms
Hermann August Theodor Harms was a German taxonomist and botanist. In 1938 he revised the pitcher plant genus Nepenthes, dividing it into three subgenera: Anurosperma, Eunepenthes and Mesonepenthes....
once again elevated N. edwardsiana to species status. This treatment was supported by Shigeo Kurata
Shigeo Kurata
is a Japanese botanist and Nepenthes taxonomist whose work in the 1960s and 1970s contributed much to the current popularity of these plants. Of particular note is his 1976 guide, Nepenthes of Mount Kinabalu....
in 1976 and has not been challenged since.
A similar 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...
from Mount Trus Madi
Mount Trus Madi
Mount Trus Madi or Trusmadi is Malaysia's second highest mountain at . It lies in the state of Sabah, close to Mount Kinabalu. The mountain supports a wide range of unique flora and fauna, perhaps most notably Nepenthes macrophylla, a species of pitcher plant.The natural hybrid Nepenthes ×...
was long considered to be N. edwardsiana. It was described in 1987 as N. edwardsiana subsp.
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
macrophylla by Johannes Marabini. A decade later, 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,...
recognised it as a separate species (N. macrophylla
Nepenthes macrophylla
Nepenthes macrophylla , the Large-Leaved Pitcher-Plant, is a tropical pitcher plant known only from a very restrictive elevation on Mount Trus Madi in Sabah, Malaysian Borneo...
) in their monograph on the genus. This interpretation has been followed by subsequent authors.
Description
Nepenthes edwardsiana is a climbing plant. The stem can attain a length of 15 m and is up to 10 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 35 cm long and circular in cross section.
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...
. The petiole is canaliculate and up to 15 cm long. It is generally winged and bears a partly amplexicaul sheath that clasps the stem for two-thirds to three-quarters of its circumference. One to three longitudinal veins are present on either side of the midrib. Pinnate veins are indistinct. 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 generally between one and two times as long as the lamina and grow to 35 cm in length.
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 is present in the bulbous portion. The mouth is elongated into a neck and has an oblique insertion. The peristome
Peristome
The word peristome is derived from the Greek peri, meaning 'around' or 'about', and stoma, 'mouth'. It is a term used to describe various anatomical features that surround an opening to an organ or structure. The term is used in plants and invertebrate animals, such as in describing the shells of...
is cylindrical and up to 30 mm wide. It bears very highly developed teeth and ribs, the latter reaching 20 mm in diameter. 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, up to 8 cm wide, and lacks appendages. An unbranched 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...
up to 20 mm long is inserted near the base of the lid. Pitchers range in colour from light yellow to dark red. The inner surface of the pitcher is usually white, contrasting sharply with the rich colouration of the outer surface. Most parts of the pitcher are very flexible, including the peristome ribs, with only the pitcher base, where the digestive zone is located, being rigid.
Nepenthes edwardsiana 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...
may be up to 30 cm long, whereas the attenuate 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...
reaches 20 cm in length. 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....
are one-flowered, up to 25 mm long, and do not possess a 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...
. 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 round to elliptic in shape and up to 5 mm long. A study of 100 pollen
Pollen
Pollen is a fine to coarse powder containing the microgametophytes of seed plants, which produce the male gametes . Pollen grains have a hard coat that protects the sperm cells during the process of their movement from the stamens to the pistil of flowering plants or from the male cone to the...
samples taken from a herbarium specimen (Sands 3651, collected at an altitude of 2600 m) found the mean pollen diameter to be 34.4 μm
Micrometre
A micrometer , is by definition 1×10-6 of a meter .In plain English, it means one-millionth of a meter . Its unit symbol in the International System of Units is μm...
(SE
Standard error (statistics)
The standard error is the standard deviation of the sampling distribution of a statistic. The term may also be used to refer to an estimate of that standard deviation, derived from a particular sample used to compute the estimate....
= 0.5; CV
Coefficient of variation
In probability theory and statistics, the coefficient of variation is a normalized measure of dispersion of a probability distribution. It is also known as unitized risk or the variation coefficient. The absolute value of the CV is sometimes known as relative standard deviation , which is...
= 7.7%).
Most parts of the plant bear 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 very short hairs, although it is not conspicuous.
Nepenthes edwardsiana varies relatively little across its range; consequently, no infraspecific taxa have been described.
Ecology
Habitat and distribution
Nepenthes edwardsiana is endemic to the highland slopes of Mount KinabaluMount Kinabalu
Mount Kinabalu is a prominent mountain on the island of Borneo in Southeast Asia. It is located in the East Malaysian state of Sabah and is protected as Kinabalu National Park, a World Heritage Site. Kinabalu is the tallest peak in Borneo's Crocker Range and is the tallest mountain in the Malay...
and the eastern side of neighbouring Mount Tambuyukon
Mount Tambuyukon
Mount Tambuyukon or Tamboyukon is Malaysia's third highest mountain at 2,579 m . It lies close to the famous Mount Kinabalu. The mountain supports a wide range of unique flora and fauna, including a number of pitcher plant species of the genus Nepenthes....
in Sabah
Sabah
Sabah is one of 13 member states of Malaysia. It is located on the northern portion of the island of Borneo. It is the second largest state in the country after Sarawak, which it borders on its southwest. It also shares a border with the province of East Kalimantan of Indonesia in the south...
, 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....
. On Mount Kinabalu, this species has been recorded from the Marai Parai
Marai Parai
Marai Parai or Marei Parei is a plateau on the northwestern side of Mount Kinabalu, in Malaysia. The mountain can be climbed from this side, although few parties attempt this route...
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...
, East Ridge, Upper Kolopis River
Kolopis River
The Kolopis River is one of the major rivers that flows through Kinabalu National Park. An area adjacent to the upper Kolopis River is home to a number of pitcher plants of the genus Nepenthes, including N. edwardsiana, N. rajah, and N. villosa, as well as two natural hybrids...
, and an area below the Kambarangoh Telekom station (below Pondok Lowii). Nepenthes edwardsiana has an altitudinal distribution of 1500–2700 m above sea level.
Anthea Phillipps
Anthea Phillipps
Anthea Phillipps B.Sc. is a British botanist. Phillipps was brought up in Sabah, Borneo as a child . She received a Botany degree from the University of Durham, England. She worked at the Sabah Museum before joining the Sabah Parks service from 1980 to 1987 as Park Ecologist, where she studied...
and Anthony Lamb
Anthony Lamb
Anthony L. Lamb M.A., Dip. Ag., D.T.A. is a British botanist, born in Sri Lanka, and specialising in the flora of Borneo. Lamb was educated at Blundell's School in Tiverton and at St John's College at Cambridge...
note that plants growing in the Racemobambos
Racemobambos
Racemobambos is a genus of bamboo and the sole genus of its subtribe, the Racemobambodinae. The genus comprises about 16 species, confined to the montane forests of Malesia .-Taxonomy:*Racemobambos gibbsiae HolttumThis genus includes:**Vietnamosasa...
bamboo
Bamboo
Bamboo is a group of perennial evergreens in the true grass family Poaceae, subfamily Bambusoideae, tribe Bambuseae. Giant bamboos are the largest members of the grass family....
forest on Mount Tambuyukon produce some of the longest and finest pitchers, having a pronounced waist and ranging in colour from pink to reddish-orange. On the Marai Parai
Marai Parai
Marai Parai or Marei Parei is a plateau on the northwestern side of Mount Kinabalu, in Malaysia. The mountain can be climbed from this side, although few parties attempt this route...
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...
of Mount Kinabalu, N. edwardsiana grows amongst shrubs up to 5 m high. Pitchers on these plants rarely exceed 30 cm. The species does not grow along the Kinabalu summit trail and so very few visitors to the park manage to see it. A specimen is kept at the "Mountain Garden" near Kinabalu Park Headquarters.
Mount Kinabalu was only formed around 1 million years ago and during the last ice age, around 20,000 to 10,000 years ago, it had an ice cap
Ice cap
An ice cap is an ice mass that covers less than 50 000 km² of land area . Masses of ice covering more than 50 000 km² are termed an ice sheet....
on its summit. As such, it appears that N. edwardsiana is a relatively recent species in evolutionary terms.
Contrary to the observations of Frederick William Burbidge
Frederick William Burbidge
Frederick William Thomas Burbidge was a British explorer who collected many rare tropical plants for the famous Veitch Nurseries. Burbidge's first job was as a gardener at Kew Gardens...
, N. edwardsiana grows not only as an epiphyte
Epiphyte
An epiphyte is a plant that grows upon another plant non-parasitically or sometimes upon some other object , derives its moisture and nutrients from the air and rain and sometimes from debris accumulating around it, and is found in the temperate zone and in the...
, but also occurs terrestrially on moss-covered rocks. It typically grows amongst ridge-top vegetation in dense mossy forest. The natural habitat of N. edwardsiana is constantly moist as the slopes are often enveloped in clouds. Despite generally occurring epiphytically, N. edwardsiana seems to grow mostly in areas with ultramafic soils, although it has also been recorded from sandstone
Sandstone
Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...
substrate
Substrate (biology)
In biology a substrate is the surface a plant or animal lives upon and grows on. A substrate can include biotic or abiotic materials and animals. For example, encrusting algae that lives on a rock can be substrate for another animal that lives on top of the algae. See also substrate .-External...
s.
Threats and conservation status
Wildfire
A wildfire is any uncontrolled fire in combustible vegetation that occurs in the countryside or a wilderness area. Other names such as brush fire, bushfire, forest fire, desert fire, grass fire, hill fire, squirrel fire, vegetation fire, veldfire, and wilkjjofire may be used to describe the same...
broke out in 9 locations in Kinabalu Park, covering a total area of 25 square kilometres and generating large amounts of smog
Smog
Smog is a type of air pollution; the word "smog" is a portmanteau of smoke and fog. Modern smog is a type of air pollution derived from vehicular emission from internal combustion engines and industrial fumes that react in the atmosphere with sunlight to form secondary pollutants that also combine...
. Hugo Steiner
Hugo Steiner
Hugo Steiner is a Swiss citizen who graduated from the University of Zurich as a physician specialising in endocrinology. He worked for several years as the leader of a research group in experimental endocrinology for Hoffmann-La Roche Ltd in Basel, Switzerland. He has also done research work in...
recalls being unable to find any pitchers of N. edwardsiana during a trip to Kinabalu in March 1999. During the El Niño period, many plants were temporarily transferred to the park nursery. These were later replanted in the "Nepenthes Garden" in Mesilau
Mesilau
Mesilau, named after Mesilau River, is an area situated at approximately 2000 m above sea level on the East Ridge of Mount Kinabalu in Kinabalu National Park, Sabah, Malaysian Borneo. It is the site of the Mesilau Nature Resort, which is owned and operated by Sutera Sanctuary Lodges...
. Since then, Ansow Gunsalam has established a nursery close to the Mesilau Lodge at the base of Kinabalu Park to protect the endangered species of that area, including N. edwardsiana.
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. edwardsiana 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 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...
. The species has also been classified as Vulnerable by the World Conservation Monitoring Centre
World Conservation Monitoring Centre
The United Nations Environment Programme's World Conservation Monitoring Centre is an executive agency of the United Nations Environment Programme, based in Cambridge in the United Kingdom. UNEP-WCMC has been part of UNEP since 2000, and has responsibility for biodiversity assessment and support...
. However, 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...
notes that since all known populations of N. edwardsiana lie within the boundaries of Kinabalu National Park
Kinabalu National Park
Kinabalu National Park or Taman Negara Kinabalu in Malay, established as one of the first national parks of Malaysia in 1964, is Malaysia's first World Heritage Site designated by UNESCO in December 2000 for its "outstanding universal values" and the role as one of the most important biological...
and are inaccessible to collectors, they "are unlikely to become threatened in the foreseeable future". Taking this into account, Clarke suggests 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...
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.
Related species
Nepenthes edwardsiana is most closely related to N. macrophyllaNepenthes macrophylla
Nepenthes macrophylla , the Large-Leaved Pitcher-Plant, is a tropical pitcher plant known only from a very restrictive elevation on Mount Trus Madi in Sabah, Malaysian Borneo...
and N. villosa
Nepenthes villosa
Nepenthes villosa , or the Villose Pitcher-Plant, is a tropical pitcher plant endemic to Mount Kinabalu and neighbouring Mount Tambuyukon in northeastern Borneo. It grows at higher altitudes than any other Bornean Nepenthes species, occurring at elevations of over 3200 m...
. There has been much taxonomic confusion surrounding the status of these three 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...
.
Changing taxonomic status
Joseph Dalton Hooker
Sir Joseph Dalton Hooker OM, GCSI, CB, MD, FRS was one of the greatest British botanists and explorers of the 19th century. Hooker was a founder of geographical botany, and Charles Darwin's closest friend...
, who described both N. edwardsiana and N. villosa, noted the similarity between the two species as follows:
This most remarkable plant [N. villosa] resembles that of edwardsiana in so many respects, especially in the size, form and disposition of the distant lamellae of the mouth, that I am inclined to suspect that it may be produced by young plants of that species, before it arrives at a stage when the pitchers have elongated necks.
Günther Beck von Mannagetta und Lerchenau was the first to treat N. edwardsiana in synonymy with N. villosa when he published his monograph on the genus in 1895.
In his 1908 monograph, John Muirhead Macfarlane
John Muirhead Macfarlane
John Muirhead Macfarlane was a Scottish botanist. He was born and educated in Scotland, where he occupied several different academic positions at the University of Edinburgh before emigrating to the United States to assume a professorial chair at the University of Pennsylvania in 1893. He held...
treated the two taxa as distinct species, writing: "Examinatione microscopica probatur, illas species distinctas esse". This was probably based on the scientific view at the time, which held that plants differing anatomically cannot be forms of the same species.
B. H. Danser
B. H. Danser
Benedictus Hubertus Danser , often abbreviated B. H. Danser, was a Dutch taxonomist and botanist...
united the species "[w]ith some hesitation" under N. villosa in his 1928 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...
". He suggested that N. villosa is a stunted form of N. edwardsiana from higher altitudes, which flowers at a "juvenile stage of development". Danser acknowledged that 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...
of N. villosa is more dense than that of N. edwardsiana, but noted that it "is a difference only of degree".
In 1936, Hermann Harms
Hermann Harms
Hermann August Theodor Harms was a German taxonomist and botanist. In 1938 he revised the pitcher plant genus Nepenthes, dividing it into three subgenera: Anurosperma, Eunepenthes and Mesonepenthes....
once again split the two species. In Nepenthes of Mount Kinabalu
Nepenthes of Mount Kinabalu
Nepenthes of Mount Kinabalu is a monograph by Shigeo Kurata on the tropical pitcher plants of Mount Kinabalu and the surrounding area of Kinabalu National Park in Sabah, Borneo. It was published in 1976 by Sabah National Parks Trustees as the second booklet of the Sabah National Parks series...
, published in 1976, Shigeo Kurata
Shigeo Kurata
is a Japanese botanist and Nepenthes taxonomist whose work in the 1960s and 1970s contributed much to the current popularity of these plants. Of particular note is his 1976 guide, Nepenthes of Mount Kinabalu....
supported this interpretation based on field observations and reference to the type descriptions.
Nepenthes macrophylla
Nepenthes macrophylla
Nepenthes macrophylla , the Large-Leaved Pitcher-Plant, is a tropical pitcher plant known only from a very restrictive elevation on Mount Trus Madi in Sabah, Malaysian Borneo...
was originally described in 1987 as a subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
of N. edwardsiana by Johannes Marabini. It was later elevated to species status by 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,...
. This interpretation was supported 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...
, who noted that N. edwardsiana and N. villosa "have more in common" than N. edwardsiana and N. macrophylla.
Species differences
Nepenthes edwardsiana and N. villosa differ in a number of morphological features. The peristome of N. villosa is more intricate and its pitchers are not elongated above the hip, unlike those of N. edwardsiana. In N. edwardsiana, the apex of the lamina is usually acute, compared to the typically emarginate apex found in N. villosa. As noted by Danser, the indumentumIndumentum
The indumentum is a covering of fine hairs or bristles on a plant or insect.In plants, the indumentum types are:*pubescent*hirsute*pilose*villous*tomentose*stellate*scabrous*scurfy...
of these species also differs, with N. villosa being densely hirsute throughout and N. edwardsiana having an inconspicuous covering of very short hairs. The two taxa can also be distinguished on the basis of their floral morphology; 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. villosa have a filiform 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...
, while those of N. edwardsiana do not.
Additionally, N. edwardsiana and N. villosa differ considerably in their altitudinal distributions. The latter species generally occurs at ultrahighland elevations (2300–3240 m), whereas N. edwardsiana is found between 1500 and 2700 m. Where their altitudinal distributions overlap, they are still identifiable as distinct species.
Whereas N. edwardsiana and N. villosa are restricted to the Kinabalu area, N. macrophylla is only found near the summit of Mount Trus Madi
Mount Trus Madi
Mount Trus Madi or Trusmadi is Malaysia's second highest mountain at . It lies in the state of Sabah, close to Mount Kinabalu. The mountain supports a wide range of unique flora and fauna, perhaps most notably Nepenthes macrophylla, a species of pitcher plant.The natural hybrid Nepenthes ×...
.
Botanists 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,...
suggest that N. edwardsiana is related to N. mira
Nepenthes mira
Nepenthes mira is a highland pitcher plant endemic to Palawan in the Philippines. It grows at elevations of 1550–1605 m above sea level....
, a species endemic to Palawan
Palawan
Palawan is an island province of the Philippines located in the MIMAROPA region or Region 4. Its capital is Puerto Princesa City, and it is the largest province in the country in terms of total area of jurisdiction. The islands of Palawan stretch from Mindoro in the northeast to Borneo in the...
in 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...
.
Natural hybrids
Natural hybrids involving N. edwardsiana appear to be relatively rare and only three have been recorded to date. N. burbidgeaeNepenthes burbidgeae
Nepenthes burbidgeae , also known as the painted pitcher plant or Burbidge's Pitcher-Plant, is a tropical pitcher plant with a patchy distribution around Mount Kinabalu and neighbouring Mount Tambuyukon in Sabah, Borneo.-Botanical history:...
× N. edwardsiana and N. edwardsiana × N. rajah
Nepenthes rajah
Nepenthes rajah is an insectivorous pitcher plant species of the Nepenthaceae family. It is endemic to Mount Kinabalu and neighbouring Mount Tambuyukon in Sabah, Malaysian Borneo. Nepenthes rajah grows exclusively on serpentine substrates, particularly in areas of seeping ground water where the...
have received little attention in the scientific literature, but N. edwardsiana × N. villosa
Nepenthes villosa
Nepenthes villosa , or the Villose Pitcher-Plant, is a tropical pitcher plant endemic to Mount Kinabalu and neighbouring Mount Tambuyukon in northeastern Borneo. It grows at higher altitudes than any other Bornean Nepenthes species, occurring at elevations of over 3200 m...
has been known since the 19th century and was initially described as a separate species, N. harryana.
N. edwardsiana × N. villosa
Nepenthes × harryana is the natural hybrid between N. edwardsiana and N. villosaNepenthes villosa
Nepenthes villosa , or the Villose Pitcher-Plant, is a tropical pitcher plant endemic to Mount Kinabalu and neighbouring Mount Tambuyukon in northeastern Borneo. It grows at higher altitudes than any other Bornean Nepenthes species, occurring at elevations of over 3200 m...
. Its two parent species are very closely related and so N. × harryana, which is roughly intermediate in form, may be difficult to distinguish from either of them.
It was originally described as a species in 1882 by Frederick William Burbidge
Frederick William Burbidge
Frederick William Thomas Burbidge was a British explorer who collected many rare tropical plants for the famous Veitch Nurseries. Burbidge's first job was as a gardener at Kew Gardens...
. John Muirhead Macfarlane
John Muirhead Macfarlane
John Muirhead Macfarlane was a Scottish botanist. He was born and educated in Scotland, where he occupied several different academic positions at the University of Edinburgh before emigrating to the United States to assume a professorial chair at the University of Pennsylvania in 1893. He held...
was the first to realise its hybrid origin and described it as such in his monograph of 1908. B. H. Danser
B. H. Danser
Benedictus Hubertus Danser , often abbreviated B. H. Danser, was a Dutch taxonomist and botanist...
wrote that N. × harryana might be a hybrid as Macfarlane suggested, or a form of N. villosa together with N. edwardsiana.
Nepenthes × harryana can be distinguished from N. villosa on the basis of its pitcher morphology. The pitchers of the hybrid are more cylindrical than those of N. villosa, whereas 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...
is more dense than that of N. edwardsiana. The hip of the pitcher cup, which is found just below the peristome in N. villosa and in the lower quarter of N. edwardsiana pitchers, is located around the middle of N. × harryana pitchers. However, N. villosa plants from Mount Tambuyukon
Mount Tambuyukon
Mount Tambuyukon or Tamboyukon is Malaysia's third highest mountain at 2,579 m . It lies close to the famous Mount Kinabalu. The mountain supports a wide range of unique flora and fauna, including a number of pitcher plant species of the genus Nepenthes....
are easier to confuse with this hybrid, as they produce pitchers that may be elongated slightly above the hip.
Nepenthes × harryana is known from a ridge above the Upper Kolopis River
Kolopis River
The Kolopis River is one of the major rivers that flows through Kinabalu National Park. An area adjacent to the upper Kolopis River is home to a number of pitcher plants of the genus Nepenthes, including N. edwardsiana, N. rajah, and N. villosa, as well as two natural hybrids...
and from two locations along the Kinabalu summit trail. Since N edwardsiana does not grow along the summit trail, it cannot be confused with this hybrid there. Burbidge wrote that N. edwardsiana, N. × harryana, and N. villosa "are quite distinct in zone of the mountain".
Cultivation
Nepenthes edwardsiana is very rare in cultivation and little information has been published on its growing requirements. Generally speaking, it is an alpine plant that requires highland conditions to grow well.In 2004, professional horticulturist Robert Sacilotto wrote a summary of measured tolerances of highland Nepenthes species, based on experiments conducted between 1996 and 2001. Out of all of the studied species, N. edwardsiana proved to be the most challenging. Cotyledon
Cotyledon
A cotyledon , is a significant part of the embryo within the seed of a plant. Upon germination, the cotyledon may become the embryonic first leaves of a seedling. The number of cotyledons present is one characteristic used by botanists to classify the flowering plants...
-stage seedlings showed a 100% mortality rate when exposed to the following conditions: relative humidity
Relative humidity
Relative humidity is a term used to describe the amount of water vapor in a mixture of air and water vapor. It is defined as the partial pressure of water vapor in the air-water mixture, given as a percentage of the saturated vapor pressure under those conditions...
constantly over 90%, water droplets present on the leaves, soil conductivity over 45 microsiemens
Siemens (unit)
The siemens is the SI derived unit of electric conductance and electric admittance. Conductance and admittance are the reciprocals of resistance and impedance respectively, hence one siemens is equal to the reciprocal of one ohm, and is sometimes referred to as the mho. In English, the term...
, and soil pH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...
above 6. However, several plants grew well in a substrate consisting of 50% perlite
Perlite
Perlite is an amorphous volcanic glass that has a relatively high water content, typically formed by the hydration of obsidian. It occurs naturally and has the unusual property of greatly expanding when heated sufficiently...
, 30% Sphagnum
Sphagnum
Sphagnum is a genus of between 151 and 350 species of mosses commonly called peat moss, due to its prevalence in peat bogs and mires. A distinction is made between sphagnum moss, the live moss growing on top of a peat bog on one hand, and sphagnum peat moss or sphagnum peat on the other, the...
moss, 10% peat moss chunks, and 10% fir
Fir
Firs are a genus of 48–55 species of evergreen conifers in the family Pinaceae. They are found through much of North and Central America, Europe, Asia, and North Africa, occurring in mountains over most of the range...
bark. A top dressing of live Sphagnum was found to provide a good anchoring point for developing roots. Humidity levels of 65 to 85% appeared to be optimal, although more mature plants over 1 year old were able to tolerate exposure to relative humidity in the range of 90 to 99% for up to three days. The highest growth rate was exhibited by plants that experienced warm days, with temperatures of 21 to 29 °C (69.8 to 84.2 F), and cool nights, with temperatures of 13 to 16 °C (55.4 to 60.8 F). The seedlings grew very slowly during the first 8 months, but their growth rate increased significantly after they reached approximately 2 cm in diameter. The plants were grown under High Pressure Sodium
Sodium vapor lamp
A sodium vapor lamp is a gas discharge lamp that uses sodium in an excited state to produce light. There are two varieties of such lamps: low pressure and high pressure...
lamps. Optimal light intensity seemed to be in the region of 7500-9100 lx
Lux
The lux is the SI unit of illuminance and luminous emittance, measuring luminous flux per unit area. It is used in photometry as a measure of the intensity, as perceived by the human eye, of light that hits or passes through a surface...
(700-850 fc
Foot-candle
A foot-candle is a non-SI unit of illuminance or light intensity widely used in photography, film, television, conservation lighting, and the lighting industry...
). Soil with a pH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...
of 4.8 to 5.4 and conductivity of less than 24 microsiemens produced the best results. Dried fruit fly
Drosophilidae
Drosophilidae is a diverse, cosmopolitan family of flies, which includes fruit flies. Another family of flies called Tephritidae also includes fruit flies. The best known species of Drosophilidae is Drosophila melanogaster, within the genus Drosophila, and this species Is used extensively for...
larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
e of the species Drosophila melanogaster
Drosophila melanogaster
Drosophila melanogaster is a species of Diptera, or the order of flies, in the family Drosophilidae. The species is known generally as the common fruit fly or vinegar fly. Starting from Charles W...
were fed to the plants once their pitchers reached around 3 mm in height. As the pitchers increased in size, they were fed with ant
Ant
Ants are social insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from wasp-like ancestors in the mid-Cretaceous period between 110 and 130 million years ago and diversified after the rise of flowering plants. More than...
s (Acanthomyops
Acanthomyops
Acanthomyops is a genus of ant in the family Formicidae. It includes the following species:* Acanthomyops arizonicus * Acanthomyops bureni Wing, 1968* Acanthomyops californicus...
sp.).
External links
- Nepenthes edwardsiana at ARKiveARKiveARKive is a global initiative with the mission of "promoting the conservation of the world's threatened species, through the power of wildlife imagery", which it does by locating and gathering films, photographs and audio recordings of the world's species into a centralised digital archive. Its...
- Nepenthes edwardsiana 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:...