Nepenthes sp. Trang
Encyclopedia
Nepenthes kerrii is a tropical pitcher plant
endemic to Tarutao National Marine Park
in southern Thailand
, where it grows at elevations of 400–500 m above sea level. This species is thought to be most closely related to N. kongkandana
.
The specific epithet kerrii refers to Irish
medical doctor Arthur Francis George Kerr
, who made the first known herbarium collection of this species.
in 1928. This specimen, Kerr 14127, was collected at an elevation of around 500 m from what is now Tarutao National Marine Park
, Satun Province
, Thailand
. It is deposited at the Bangkok Herbarium (BK). Italian
naturalist Marcello Catalano
came across this plant material in 2006 and recognised it as a previously unknown taxon
. The specimen's label identified it as "N. gracilis
" and appeared to state that it was collected at 1500 m (it was later realised that it actually read "c.
500 m"). In 2007, Catalano travelled to Tarutao but was unable to relocate the taxon in the wild. With the help of local rangers, however, he was able to determine that it grew in a certain remote area of the park. Several months later, the rangers organised an expedition on their own and were successful in finding the plants. They sent photographs of the taxon to Catalano and these convinced him that it represented a new species.
In January 2008, Catalano made two attempts to reach the site discovered by the rangers. Both proved unsuccessful due to the time and effort involved. That same month Catalano met with Stewart McPherson
on the Thai mainland and informed him of the findings. McPherson then travelled to Tarutao National Marine Park on his own. After what he described as "the worst treck of my life", McPherson succeeded in relocating the plants. He returned with seeds and photographs, mostly of the upper pitchers.
The first published description of N. kerrii appeared in volume I of Stewart McPherson's
2009 monograph, Pitcher Plants of the Old World
. It was included as an "incompletely diagnosed taxon" under the name N. sp. Trang. McPherson wrote that it was known with certainty only from Thailand, but had also been reported from the Malaysian island of Langkawi
. He considered it to be most closely related to N. kampotiana
, writing that "[m]ore extensive observations are required in order to determine whether this taxon merely represents variation within N. kampotiana or is a distinct species".
Around this time, Catalano set to work on the formal description of N. kerrii. However, he lacked all the necessary measurements and photographs to complete it and so, in 2009, he once again attempted to reach the wild plants in Tarutao, but this time the expedition was thwarted by torrential rains
. Upon returning to Italy
, Catalano contacted Trongtham Kruetreepradit, a Thai local, who travelled to the plants during the dry season
and provided the information Catalano needed to finish the description.
Nepenthes kerrii was formally described
by Marcello Catalano
and Trongtham Kruetreepradit in Catalano's 2010 book, Nepenthes della Thailandia. The description was reviewed by Alastair Robinson
, while Andreas Fleischmann provided the Latin
translation. Kerr 14127 was designated as the holotype
. Contrary to McPherson's interpretation, Catalano and Kruetreepradit excluded the Langkawi taxon
from their circumscription of N. kerrii and identified N. kongkandana
as its closest relative.
is terete and 3–5 mm in diameter. It is typically self-supporting and unbranched. Internode
s are up to 8.5 cm long. The stem ranges in colour from green to red.
Leaves are sessile and coriaceous in texture. The lamina (leaf blade) is obovate, measures up to 31 cm in length by 3 cm in width, and is around 0.5 mm thick. Its apex is acuminate and it is attenuate at the base, clasping the stem for around three-quarters of its circumference. Three longitudinal veins are present on either side of the midrib, restricted to the distal quarter of the lamina. Pinnate veins are also visible, and arise obliquely from the midrib. Tendril
s are up to 30 cm long and 3 mm in diameter. They are coiled in upper pitchers. The laminae are light green, while the midrib and tendrils may be green to red.
Rosette and lower pitchers are either wholly ovate or only ovate in the basal half of the pitcher cup and narrower above. They measure up to 14 cm in height by 6 cm in width. The hip, which is only faintly visible, is positioned either in the middle or in the upper half of the trap. A pair of wings (≤8 mm wide) runs down the ventral surface of the pitcher cup, bearing narrow fringe elements. The pitcher mouth is oval and has an oblique insertion. The peristome
is cylindrical and up to 12 mm wide, with teeth up to 0.5 mm long. The pitcher lid or operculum
is round with a slightly cordate base and an irregularly wavy margin. It measures up to 4.3 cm in length by 4.7 cm in width, being as large as the mouth. The lower surface of the lid does not have any appendages, but bears numerous crater-like glands (≤1 mm in diameter), the largest of which are located around the midline. The spur, which is inserted near the base of the lid, is up to 7 mm long and may be simple or branched. Terrestrial pitchers are typically orange with red blotches on their outer surface. These red markings are also found in the waxy zone of the inner surface. The peristome and lid range in colour from orange to red.
The tubulose upper pitchers are similar in size to their terrestrial counterparts, measuring up to 15 cm in height by 3.5 cm in width. The wings are up to 4 mm wide and spaced 4–6 mm apart. The pitcher mouth is orbicular or broadly ovate and has an oblique insertion. The peristome is lobate and has a distinct neck. The lid as well as other parts of the pitcher are similar to those found in terrestrial traps. Aerial pitchers have a lighter pigmentation than their lower counterparts, being green to yellow on the outer surface. Red blotches are present on the waxy inner surface. The peristome may be yellow or red striped, while the lid is green to yellow and commonly red on its lower surface.
Nepenthes kerrii has a racemose
inflorescence
up to 130 cm long. In male plants, the inflorescence reaches 90 cm in length, of which the peduncle
can constitute up to 65 cm and the rachis
up to 27 cm, and bears around 120 flowers singly on pedicels
measuring 6–8 mm in length. The androphore is up to 1.5 mm long. Tepal
s are round or elliptic and up to 4 mm long by 3 mm wide. Those of male flowers may be green or red, whereas those of females are always green. The female inflorescence is similar in structure to the male one, but differs in having a rachis up to 25 cm long with longer pedicels of 10–23 mm. Nepenthes kerrii exhibits modified seed
morphology, whereby the seed wings are significantly reduced. This is thought to be an adaptation to the species's island habitat; the lack of prominent seed wings likely serves to prevent strong winds from blowing them into the sea.
An indumentum
of brown hairs (0.1 mm long) is present on the leaf axils and inflorescence.
Like all pyrophytic
Nepenthes from Indochina
, N. kerrii has a well-developed rootstock.
in Satun Province
, southern Thailand
. Reports of this species from the Malaysian island of Langkawi
represent a different, although similar, taxon
. The species has an altitudinal range of 400–500 m above sea level.
Its typical habitat is open savannah
and grassland
, where it grows terrestrially in sand
y soil. This soil consists of a quartz
-rich layer up to 30 cm deep over a base of granite
. During the dry season
, this substrate
can become very hot and dry, hardening considerably as a result. Nepenthes kerrii is not sympatric
with any other Nepenthes species in the wild and no natural hybrids involving it have been recorded.
In Pitcher Plants of the Old World
, Stewart McPherson
writes that populations of N. kerrii "are extremely inaccessible and not threatened at present".
. It is also similar to the Indochinese
endemics N. andamana
, N. bokorensis
, and N. suratensis
.
Nepenthes kerrii can be distinguished from all of these species, with the exception of N. kongkandana, on the basis of its laminae, which are obovate as opposed to linear to lanceolate. It also differs in having a persistent indumentum
restricted to the leaf axils. In contrast, N. andamana and N. suratensis have a caducous indumentum on the upper parts of the plant, N. kongkandana has 0.3 mm long hairs covering the whole plant, and N. bokorensis has a variable indumentum covering all vegetative and floral parts. In addition, the androphore of N. kerrii is considerably shorter than that of N. bokorensis.
In their description of N. kerrii, Catalano and Kruetreepradit also note a number of other vegetative features that separate this species from N. kongkandana. The lower pitchers of N. kerrii are narrowly ovate with the hip positioned in the middle or upper portion of the trap, whereas those of N. kongkandana are tubular or slightly ventricose with the hip in the middle or lower portion. Nepenthes kerrii also produces longer tendrils that are two to three times as long as the pitcher; the tendrils of N. kongkandana are similar in length to the pitchers they bear. The peristome of the aerial pitchers is also distinct, being lobed and often striped with a distinct neck in N. kerrii and always lacking these features in N. kongkandana. Finally, the distance between the ventral wings of the upper pitchers is greater in N. kongkandana (10–12 mm versus 4–6 mm).
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 Tarutao National Marine Park
Tarutao National Marine Park
Tarutao National Marine Park consists of 51 islands located in the Andaman Sea, off the coast of Satun Province of Southern Thailand. The Tarutao National Marine Park consists of two island groups: Tarutao and Adang-Rawi , which are scattered from 20 to 70 kilometers distance from the...
in southern Thailand
Thailand
Thailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...
, where it grows at elevations of 400–500 m above sea level. This species is thought to be most closely related to N. kongkandana
Nepenthes kongkandana
Nepenthes kongkandana is an undescribed tropical pitcher plant endemic to Songkhla Province in southern Thailand. This species is closely related to N. kerrii.-External links:*...
.
The specific epithet kerrii refers to Irish
Ireland
Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...
medical doctor Arthur Francis George Kerr
Arthur Francis George Kerr
Arthur Francis George Kerr was an Irish medical doctor. He is known particularly now for his botanical work, which was important for the study of the flora of Thailand....
, who made the first known herbarium collection of this species.
Botanical history
The first known collection of N. kerrii was made by Arthur Francis George KerrArthur Francis George Kerr
Arthur Francis George Kerr was an Irish medical doctor. He is known particularly now for his botanical work, which was important for the study of the flora of Thailand....
in 1928. This specimen, Kerr 14127, was collected at an elevation of around 500 m from what is now Tarutao National Marine Park
Tarutao National Marine Park
Tarutao National Marine Park consists of 51 islands located in the Andaman Sea, off the coast of Satun Province of Southern Thailand. The Tarutao National Marine Park consists of two island groups: Tarutao and Adang-Rawi , which are scattered from 20 to 70 kilometers distance from the...
, Satun Province
Satun Province
Satun is one of the southern provinces of Thailand. Neighboring provinces are Trang, Phatthalung and Songkhla...
, Thailand
Thailand
Thailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...
. It is deposited at the Bangkok Herbarium (BK). Italian
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
naturalist Marcello Catalano
Marcello Catalano
Marcello Catalano is an Italian naturalist and author specializing in carnivorous plants. As a result of this interest, which began in 1985, Catalano founded the Italian Carnivorous Plant Society and its quarterly magazine, AIPC News , at the end of the 1990s.From 2000 to 2004, he...
came across this plant material in 2006 and recognised it as a previously unknown 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...
. The specimen's label identified it as "N. gracilis
Nepenthes gracilis
Nepenthes gracilis , or the Slender Pitcher-Plant, is a very common lowland pitcher plant that is widespread in the Sunda region. It has been recorded from Borneo, Peninsular Malaysia, Singapore, central Sulawesi, Sumatra, and southernmost Thailand...
" and appeared to state that it was collected at 1500 m (it was later realised that it actually read "c.
Circa
Circa , usually abbreviated c. or ca. , means "approximately" in the English language, usually referring to a date...
500 m"). In 2007, Catalano travelled to Tarutao but was unable to relocate the taxon in the wild. With the help of local rangers, however, he was able to determine that it grew in a certain remote area of the park. Several months later, the rangers organised an expedition on their own and were successful in finding the plants. They sent photographs of the taxon to Catalano and these convinced him that it represented a new species.
In January 2008, Catalano made two attempts to reach the site discovered by the rangers. Both proved unsuccessful due to the time and effort involved. That same month Catalano met with 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....
on the Thai mainland and informed him of the findings. McPherson then travelled to Tarutao National Marine Park on his own. After what he described as "the worst treck of my life", McPherson succeeded in relocating the plants. He returned with seeds and photographs, mostly of the upper pitchers.
The first published description of N. kerrii appeared in volume I of Stewart McPherson's
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....
2009 monograph, Pitcher Plants of the Old World
Pitcher Plants of the Old World
Pitcher Plants of the Old World is a two-volume monograph by Stewart McPherson on the pitcher plants of the genera Nepenthes and Cephalotus. It was published in May 2009 by Redfern Natural History Productions...
. It was included as an "incompletely diagnosed taxon" under the name N. sp. Trang. McPherson wrote that it was known with certainty only from Thailand, but had also been reported from the Malaysian island of Langkawi
Langkawi
Langkawi, officially known as Langkawi, the Jewel of Kedah is an archipelago of 104 islands in the Andaman Sea, some 30 km off the mainland coast of northwestern Malaysia. The islands are a part of the state of Kedah, which is adjacent to the Thai border...
. He considered it to be most closely related to N. kampotiana
Nepenthes kampotiana
Nepenthes kampotiana is a tropical pitcher plant native to southern Cambodia, eastern Thailand, and western Vietnam. The specific epithet kampotiana refers to the Cambodian city of Kampot, close to which the first specimens of this species were collected.This species is closely related to...
, writing that "[m]ore extensive observations are required in order to determine whether this taxon merely represents variation within N. kampotiana or is a distinct species".
Around this time, Catalano set to work on the formal description of N. kerrii. However, he lacked all the necessary measurements and photographs to complete it and so, in 2009, he once again attempted to reach the wild plants in Tarutao, but this time the expedition was thwarted by torrential rains
Wet season
The the wet season, or rainy season, is the time of year, covering one or more months, when most of the average annual rainfall in a region occurs. The term green season is also sometimes used as a euphemism by tourist authorities. Areas with wet seasons are dispersed across portions of the...
. Upon returning to Italy
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
, Catalano contacted Trongtham Kruetreepradit, a Thai local, who travelled to the plants during the dry season
Dry season
The dry season is a term commonly used when describing the weather in the tropics. The weather in the tropics is dominated by the tropical rain belt, which oscillates from the northern to the southern tropics over the course of the year...
and provided the information Catalano needed to finish the description.
Nepenthes kerrii 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 Marcello Catalano
Marcello Catalano
Marcello Catalano is an Italian naturalist and author specializing in carnivorous plants. As a result of this interest, which began in 1985, Catalano founded the Italian Carnivorous Plant Society and its quarterly magazine, AIPC News , at the end of the 1990s.From 2000 to 2004, he...
and Trongtham Kruetreepradit in Catalano's 2010 book, Nepenthes della Thailandia. The description was reviewed by Alastair Robinson
Alastair Robinson
Dr. Alastair S. Robinson is a British-American taxonomist and field botanist specialising in the carnivorous plant genus Nepenthes...
, while Andreas Fleischmann provided the Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
translation. Kerr 14127 was designated as the holotype
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
. Contrary to McPherson's interpretation, Catalano and Kruetreepradit excluded the Langkawi 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 their circumscription of N. kerrii and identified N. kongkandana
Nepenthes kongkandana
Nepenthes kongkandana is an undescribed tropical pitcher plant endemic to Songkhla Province in southern Thailand. This species is closely related to N. kerrii.-External links:*...
as its closest relative.
Description
Nepenthes kerrii is a climbing plant growing to a height of approximately 4 m. The stemPlant stem
A stem is one of two main structural axes of a vascular plant. The stem is normally divided into nodes and internodes, the nodes hold buds which grow into one or more leaves, inflorescence , conifer cones, roots, other stems etc. The internodes distance one node from another...
is terete and 3–5 mm in diameter. It is typically self-supporting and unbranched. Internode
Plant 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 8.5 cm long. The stem ranges in colour from green to red.
Leaves are sessile and coriaceous in texture. The lamina (leaf blade) is obovate, measures up to 31 cm in length by 3 cm in width, and is around 0.5 mm thick. Its apex is acuminate and it is attenuate at the base, clasping the stem for around three-quarters of its circumference. Three longitudinal veins are present on either side of the midrib, restricted to the distal quarter of the lamina. Pinnate veins are also visible, and arise obliquely from the midrib. 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 30 cm long and 3 mm in diameter. They are coiled in upper pitchers. The laminae are light green, while the midrib and tendrils may be green to red.
Rosette and lower pitchers are either wholly ovate or only ovate in the basal half of the pitcher cup and narrower above. They measure up to 14 cm in height by 6 cm in width. The hip, which is only faintly visible, is positioned either in the middle or in the upper half of the trap. A pair of wings (≤8 mm wide) runs down the ventral surface of the pitcher cup, bearing narrow fringe elements. The pitcher mouth is oval 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 12 mm wide, with teeth up to 0.5 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 round with a slightly cordate base and an irregularly wavy margin. It measures up to 4.3 cm in length by 4.7 cm in width, being as large as the mouth. The lower surface of the lid does not have any appendages, but bears numerous crater-like glands (≤1 mm in diameter), the largest of which are located around the midline. The spur, which is inserted near the base of the lid, is up to 7 mm long and may be simple or branched. Terrestrial pitchers are typically orange with red blotches on their outer surface. These red markings are also found in the waxy zone of the inner surface. The peristome and lid range in colour from orange to red.
The tubulose upper pitchers are similar in size to their terrestrial counterparts, measuring up to 15 cm in height by 3.5 cm in width. The wings are up to 4 mm wide and spaced 4–6 mm apart. The pitcher mouth is orbicular or broadly ovate and has an oblique insertion. The peristome is lobate and has a distinct neck. The lid as well as other parts of the pitcher are similar to those found in terrestrial traps. Aerial pitchers have a lighter pigmentation than their lower counterparts, being green to yellow on the outer surface. Red blotches are present on the waxy inner surface. The peristome may be yellow or red striped, while the lid is green to yellow and commonly red on its lower surface.
Nepenthes kerrii 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...
up to 130 cm long. In male plants, the inflorescence reaches 90 cm in length, of which 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...
can constitute up to 65 cm and 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...
up to 27 cm, and bears around 120 flowers 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....
measuring 6–8 mm in length. The androphore is up to 1.5 mm long. 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 are round or elliptic and up to 4 mm long by 3 mm wide. Those of male flowers may be green or red, whereas those of females are always green. The female inflorescence is similar in structure to the male one, but differs in having a rachis up to 25 cm long with longer pedicels of 10–23 mm. Nepenthes kerrii exhibits modified seed
Seed
A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...
morphology, whereby the seed wings are significantly reduced. This is thought to be an adaptation to the species's island habitat; the lack of prominent seed wings likely serves to prevent strong winds from blowing them into the sea.
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 brown hairs (0.1 mm long) is present on the leaf axils and inflorescence.
Like all pyrophytic
Pyrophyte
Pyrophytes are plants which have adapted to tolerate fire. "Pyrophyte" comes from the ancient Greek "pyros" and "phytos" .Fire acts favorably for some species. "Passive pyrophytes" resist the effects of fire, particularly when it passes over quickly, and hence can out-compete less resistant...
Nepenthes from Indochina
Indochina
The Indochinese peninsula, is a region in Southeast Asia. It lies roughly southwest of China, and east of India. The name has its origins in the French, Indochine, as a combination of the names of "China" and "India", and was adopted when French colonizers in Vietnam began expanding their territory...
, N. kerrii has a well-developed rootstock.
Ecology
Nepenthes kerrii is endemic to Tarutao National Marine ParkTarutao National Marine Park
Tarutao National Marine Park consists of 51 islands located in the Andaman Sea, off the coast of Satun Province of Southern Thailand. The Tarutao National Marine Park consists of two island groups: Tarutao and Adang-Rawi , which are scattered from 20 to 70 kilometers distance from the...
in Satun Province
Satun Province
Satun is one of the southern provinces of Thailand. Neighboring provinces are Trang, Phatthalung and Songkhla...
, southern Thailand
Thailand
Thailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...
. Reports of this species from the Malaysian island of Langkawi
Langkawi
Langkawi, officially known as Langkawi, the Jewel of Kedah is an archipelago of 104 islands in the Andaman Sea, some 30 km off the mainland coast of northwestern Malaysia. The islands are a part of the state of Kedah, which is adjacent to the Thai border...
represent a different, although 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...
. The species has an altitudinal range of 400–500 m above sea level.
Its typical habitat is open savannah
Savannah
Savannah or savanna is a type of grassland.It can also mean:-People:* Savannah King, a Canadian freestyle swimmer* Savannah Outen, a singer who gained popularity on You Tube...
and grassland
Grassland
Grasslands are areas where the vegetation is dominated by grasses and other herbaceous plants . However, sedge and rush families can also be found. Grasslands occur naturally on all continents except Antarctica...
, where it grows terrestrially in sand
Sand
Sand is a naturally occurring granular material composed of finely divided rock and mineral particles.The composition of sand is highly variable, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal...
y soil. This soil consists of a quartz
Quartz
Quartz is the second-most-abundant mineral in the Earth's continental crust, after feldspar. It is made up of a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2. There are many different varieties of quartz,...
-rich layer up to 30 cm deep over a base of granite
Granite
Granite is a common and widely occurring type of intrusive, felsic, igneous rock. Granite usually has a medium- to coarse-grained texture. Occasionally some individual crystals are larger than the groundmass, in which case the texture is known as porphyritic. A granitic rock with a porphyritic...
. During the dry season
Dry season
The dry season is a term commonly used when describing the weather in the tropics. The weather in the tropics is dominated by the tropical rain belt, which oscillates from the northern to the southern tropics over the course of the year...
, this 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...
can become very hot and dry, hardening considerably as a result. Nepenthes kerrii is not 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 any other Nepenthes species in the wild and no natural hybrids involving it have been recorded.
In Pitcher Plants of the Old World
Pitcher Plants of the Old World
Pitcher Plants of the Old World is a two-volume monograph by Stewart McPherson on the pitcher plants of the genera Nepenthes and Cephalotus. It was published in May 2009 by Redfern Natural History Productions...
, 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....
writes that populations of N. kerrii "are extremely inaccessible and not threatened at present".
Related species
Nepenthes kerrii appears to be most closely related to N. kongkandanaNepenthes kongkandana
Nepenthes kongkandana is an undescribed tropical pitcher plant endemic to Songkhla Province in southern Thailand. This species is closely related to N. kerrii.-External links:*...
. It is also similar to the Indochinese
Indochina
The Indochinese peninsula, is a region in Southeast Asia. It lies roughly southwest of China, and east of India. The name has its origins in the French, Indochine, as a combination of the names of "China" and "India", and was adopted when French colonizers in Vietnam began expanding their territory...
endemics N. andamana
Nepenthes andamana
Nepenthes andamana is a tropical pitcher plant endemic to Phang Nga Province, Thailand, where it grows at sea level in coastal savannah and grassland...
, N. bokorensis
Nepenthes bokorensis
Nepenthes bokorensis is a tropical pitcher plant endemic to Cambodia. It is known from Mount Bokor in the south of the country, and an as yet undetermined specimen suggests that it may also be present in other parts of the Dâmrei Mountains of Kampot Province...
, and N. suratensis
Nepenthes suratensis
Nepenthes suratensis is a tropical pitcher plant endemic to Surat Thani Province, Thailand, where it grows at sea level in coastal savannah and grassland...
.
Nepenthes kerrii can be distinguished from all of these species, with the exception of N. kongkandana, on the basis of its laminae, which are obovate as opposed to linear to lanceolate. It also differs in having a persistent 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...
restricted to the leaf axils. In contrast, N. andamana and N. suratensis have a caducous indumentum on the upper parts of the plant, N. kongkandana has 0.3 mm long hairs covering the whole plant, and N. bokorensis has a variable indumentum covering all vegetative and floral parts. In addition, the androphore of N. kerrii is considerably shorter than that of N. bokorensis.
In their description of N. kerrii, Catalano and Kruetreepradit also note a number of other vegetative features that separate this species from N. kongkandana. The lower pitchers of N. kerrii are narrowly ovate with the hip positioned in the middle or upper portion of the trap, whereas those of N. kongkandana are tubular or slightly ventricose with the hip in the middle or lower portion. Nepenthes kerrii also produces longer tendrils that are two to three times as long as the pitcher; the tendrils of N. kongkandana are similar in length to the pitchers they bear. The peristome of the aerial pitchers is also distinct, being lobed and often striped with a distinct neck in N. kerrii and always lacking these features in N. kongkandana. Finally, the distance between the ventral wings of the upper pitchers is greater in N. kongkandana (10–12 mm versus 4–6 mm).