Nepenthes izumiae
Encyclopedia
Nepenthes izumiae is a tropical pitcher plant
endemic to Sumatra
, where it grows in montane forest at 1700–1900 m above sea level. It appears to be most closely related to N. lingulata
and N. singalana
.
The specific epithet izumiae honours Izumi Davis, wife of Troy Davis, one of the describing authors.
in Charles Clarke
's 2001 monograph, Nepenthes of Sumatra and Peninsular Malaysia
, under the name "Nepenthes species B". Clarke considered it to be most closely allied to N. singalana
, writing that "[f]urther research is required to determine whether or not this is simply an unusual variety of N. singalana, or whether it warrants description as a distinct species". Flowering size specimens of N. izumiae, labelled as N. singalana from Mount Talakmau
, were already in cultivation before the species was formally published.
Nepenthes izumiae was formally described
by Troy Davis, Charles Clarke
and Rusjdi Tamin in a 2003 issue of the botanical journal Blumea
. Clarke, Davis & Tamin 1309 was designated as the holotype
. This specimen was collected in the Barisan Mountains
, north of Bukittinggi
, on July 13, 2000. It is deposited at the Herbarium Universitas Andalas (ANDA) of Andalas University
in Padang
, West Sumatra
.
The next detailed treatment of N. izumiae appeared in Stewart McPherson
's 2009 monograph, Pitcher Plants of the Old World
.
ranges in colour from green to reddish.
The lamina (leaf blade) varies in shape and may be linear, lanceolate, or spathulate. It measures up to 28 cm in length by 8 cm in width and may have a frilled margin. The lamina has an acute apex and narrows towards the base, widening again just before the point of attachment. Longitudinal veins are inconspicuous. Tendril
s are up to 30 cm long and often have a sub-apical or even peltate insertion, joining the lamina on the underside, before the apex. The lamina is green throughout, whereas the midrib and tendril may be green to reddish.
Rosette and lower pitchers are typically ovate in the basal quarter to half of the pitcher cup, becoming cylindrical and sometimes slightly infundibular above. A conspicuous hip often delimits these two parts of the trap. Terrestrial pitchers may be quite large, reaching 30 cm in height by 6 cm in width. A pair of fringed wings (≤6 mm wide) runs down the ventral surface of the trap, bearing filaments up to 12 mm long. The peristome
is cylindrical at the front and becomes flattened and broader towards the sides and rear, measuring up to 3 cm in width. It bears ribs up to 2 mm high and spaced up to 2.5 mm apart. These ribs terminate in teeth (≤8 mm long) on the inner margin of the peristome, the largest being located towards the top. There is often a gap of several millimetres separating the two lobes of the peristome directly below the lid. The pitcher lid or operculum
is ovate to orbicular and typically has a cordate base as well as a frilled margin. It measures up to 6 cm in length by 4.5 cm in width. A triangular or hook-shaped basal crest (≤1 cm long) is commonly present on the lower surface of the lid. An unbranched spur measuring up to 10 mm in length is inserted near the base of the lid. Lower pitchers typically have a very dark pigmentation, being purplish-black throughout. However, the indumentum
covering the traps can give them an orange or brownish sheen. The peristome is generally purple, black, or dark brown, but may have lighter coloured teeth ranging from green, through yellow, to white. The inner surface of the pitcher may be light yellow, white, or light purple, and often bears purple speckles. The pitcher lid is often yellow or green on the underside and dark purple on its upper surface. Occasionally, the pitcher may be yellowish-green throughout with a black peristome.
Upper pitchers are narrowly infundibular in the basal third to half of the pitcher cup and cylindrical above. A constriction and associated hip often delimit these two parts. Aerial traps are smaller than their terrerstrial counterparts, reaching 20 cm in height by 4 cm in width. In upper pitchers, the wings are reduced to ribs. The peristome, which reaches up to 8 mm in width, is cylindrical and expanded at the sides and rear. It bears ribs up to 0.5 mm high and spaced up to 0.5 mm apart as well as teeth up to 1.5 mm long. The pitcher lid is sub-orbicular to slightly ovate and has a cordate base. It measures up to 4.5 cm in length by 4 cm in width. It may or may not bear an appendage on its underside. The spur is simple or branched and attains a length of 5 mm. Upper pitchers exhibit a similar pigmentation to lower pitchers, but are typically lighter.
Nepenthes izumiae has a racemose
inflorescence
up to 18 cm long, of which the peduncle
constitutes up to 10 cm and the rachis
up to 8 cm. Flowers are borne solitarily on pedicels
(≤5 mm long) that lack bract
s. Tepal
s are ovate and up to 6 mm long. Fruit
s reach 15 mm in length. The structure of the male inflorescence has not been documented.
An indumentum
of red, brown or white hairs up to 1 mm long may be present on the laminar margins, pitchers (particularly lower ones), tendrils, and parts of the inflorescence.
in the Barisan Mountains
of West Sumatra
, Indonesia
. In the interests of conservation, the exact locality was not disclosed in the formal description. The species has an altitudinal range of 1700–1900 m above sea level.
The typical habitat of N. izumiae is upper montane mossy forest, where conditions are moist and the plants experience diffused sunlight. At one location, the vegetation is dominated by fern
s of the genera
Dicranopteris and Dipteris. The species is most commonly epiphytic
, often being found on moss
-covered branches, but it can also grow terrestrially over a layer of moss. Nepenthes izumiae is naturally sympatric
with N. dubia
and N. gymnamphora
, and a natural hybrid with the former has been recorded.
The only known populations of N. izumiae lie outside the boundaries of national park
s. Stewart McPherson
considers the species to be "at significant risk of being poached and over collected" and cites the "rapid demise" of N. aristolochioides
, another highly sought-after Sumatran plant, as an example of the possible fate of this species. Nepenthes izumiae is also threatened by forest and shrub fires as well as land development.
and N. singalana
.
With the former, N. izumiae shares the general morphology and colouration of its pitchers. However, it can be easily distinguished from that species as it lacks the highly developed filiform appendage that gives N. lingulata its name. It also differs in typically having an orbicular lid, as opposed to the triangular lid of N. lingulata, as well as broader pitchers with more highly developed peristome ribs and an unbranched spur
. In addition, N. lingulata completely lacks nectar glands on the underside of the lid and has a very dense woolly indumentum
.
Nepenthes izumiae differs from N. singalana in that it often possesses a basal crest on the underside of the lid; this structure is never found in N. singalana. Nepenthes izumiae also differs in several other vegetative features: it has broader laminae with persistent hairs on the margins, longer and narrower terrestrial traps, and a thinner peristome with finer ribs and teeth. In addition, whereas N. izumiae is typically epiphytic
in growth habit, N. singalana is mostly terrestrial.
Nepenthes izumiae may also bear a resemblance to N. bongso
and N. ovata
, but both of these species have entirely infundibular upper pitchers and often have spathulate laminae with glabrous margins. Nepenthes spathulata
could also be confused with N. izumiae, but it can be distinguished on the basis of its wider laminae and pitchers, the latter typically also being lighter in colouration.
and N. jacquelineae
.
A single mature female plant of N. dubia × N. izumiae grows along the summit trail on Mount Talakmau
. It produces infundibular upper pitchers that are yellowish-green in colouration. The pitchers are relatively small, reaching only around 10 cm in height. As in N. dubia, the stem and tendrils are purplish-red. The lamina is green with a red midrib. Nepenthes dubia × N. izumiae differs most obviously from N. dubia in having an ovate lid that is never reflexed beyond 180 degrees. This hybrid is listed as N. dubia × N. singalana in Charles Clarke
's 2001 monograph, Nepenthes of Sumatra and Peninsular Malaysia
, because at the time of its publication it was uncertain whether N. izumiae represented a distinct species.
Pitcher plant
Pitcher plants are carnivorous plants whose prey-trapping mechanism features a deep cavity filled with liquid known as a pitfall trap. It has been widely assumed that the various sorts of pitfall trap evolved from rolled leaves, with selection pressure favouring more deeply cupped leaves over...
endemic to Sumatra
Sumatra
Sumatra is an island in western Indonesia, westernmost of the Sunda Islands. It is the largest island entirely in Indonesia , and the sixth largest island in the world at 473,481 km2 with a population of 50,365,538...
, where it grows in montane forest at 1700–1900 m above sea level. It appears to be most closely related to N. lingulata
Nepenthes lingulata
Nepenthes lingulata is a tropical pitcher plant endemic to northern Sumatra. The species is characterised by the highly developed appendage present on the underside of the lid...
and N. singalana
Nepenthes singalana
Nepenthes singalana is a highland Nepenthes pitcher plant species native to the island of Sumatra. It is most closely related to N. diatas and N. spathulata.-Taxonomy:...
.
The specific epithet izumiae honours Izumi Davis, wife of Troy Davis, one of the describing authors.
Botanical history
The species was mentioned as an undescribed taxonUndescribed taxon
In taxonomy, an undescribed taxon is a taxon that has been discovered, but not yet formally described and named. The various Nomenclature Codes specify the requirements for a new taxon to be validly described and named. Until such a description has been published, the taxon has no formal or...
in 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...
's 2001 monograph, Nepenthes of Sumatra and Peninsular Malaysia
Nepenthes of Sumatra and Peninsular Malaysia
Nepenthes of Sumatra and Peninsular Malaysia is a monograph by Charles Clarke on the tropical pitcher plants of Sumatra, Peninsular Malaysia, and their minor surrounding islands. It was published in 2001 by Natural History Publications...
, under the name "Nepenthes species B". Clarke considered it to be most closely allied to N. singalana
Nepenthes singalana
Nepenthes singalana is a highland Nepenthes pitcher plant species native to the island of Sumatra. It is most closely related to N. diatas and N. spathulata.-Taxonomy:...
, writing that "[f]urther research is required to determine whether or not this is simply an unusual variety of N. singalana, or whether it warrants description as a distinct species". Flowering size specimens of N. izumiae, labelled as N. singalana from Mount Talakmau
Mount Talakmau
Talakmau is a volcano in West Sumatra, Indonesia. Its elevation is 2,919 m .-External links :*...
, were already in cultivation before the species was formally published.
Nepenthes izumiae 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 Troy Davis, 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...
and Rusjdi Tamin in a 2003 issue of the botanical journal Blumea
Blumea (journal)
Blumea - Journal of Plant Taxonomy and Plant Geography is a peer-reviewed journal of botany published by the National Herbarium of the Netherlands.Except for a short period during World War II, Blumea has been published continuously since 1934...
. Clarke, Davis & Tamin 1309 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...
. This specimen was collected in the Barisan Mountains
Barisan Mountains
The Bukit Barisan or the Barisan Mountains are a mountain range on the western side of Sumatra, Indonesia, covering nearly 1,700 km from the north to the south of the island. The Bukit Barisan range consists primarily of volcanoes shrouded in dense jungle cover, including Sumatran tropical pine...
, north of Bukittinggi
Bukittinggi
Bukittinggi is one of the larger cities in West Sumatra, Indonesia, with a population of over 91,000 people and an area of 25.24 km². It is situated in the Minangkabau highlands, 90 km by road from the West Sumatran capital city of Padang. It is located at , near the volcanoes Mount...
, on July 13, 2000. It is deposited at the Herbarium Universitas Andalas (ANDA) of Andalas University
Andalas University
Andalas University is the oldest university in Indonesia outside of Java. The university consists of eleven faculties, with most located at the main campus Limau Manis, 12 km from the center of Padang, West Sumatra. This campus occupies 5 km², at an elevation of about 100 m. The Faculty...
in Padang
Padang, Indonesia
Padang is the capital and largest city of West Sumatra, Indonesia. It is located on the western coast of Sumatra at . It has an area of and a population of over 833,000 people at the 2010 Census.-History:...
, West Sumatra
West Sumatra
West Sumatra is a province of Indonesia. It lies on the west coast of the island Sumatra. It borders the provinces of North Sumatra to the north, Riau and Jambi to the east, and Bengkulu to the southeast. It includes the Mentawai Islands off the coast...
.
The next detailed treatment of N. izumiae appeared in 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....
's 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...
.
Description
Nepenthes izumiae is a climbing plant growing to a height of 8 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...
ranges in colour from green to reddish.
The lamina (leaf blade) varies in shape and may be linear, lanceolate, or spathulate. It measures up to 28 cm in length by 8 cm in width and may have a frilled margin. The lamina has an acute apex and narrows towards the base, widening again just before the point of attachment. Longitudinal veins are inconspicuous. 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 often have a sub-apical or even peltate insertion, joining the lamina on the underside, before the apex. The lamina is green throughout, whereas the midrib and tendril may be green to reddish.
Rosette and lower pitchers are typically ovate in the basal quarter to half of the pitcher cup, becoming cylindrical and sometimes slightly infundibular above. A conspicuous hip often delimits these two parts of the trap. Terrestrial pitchers may be quite large, reaching 30 cm in height by 6 cm in width. A pair of fringed wings (≤6 mm wide) runs down the ventral surface of the trap, bearing filaments up to 12 mm long. 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 at the front and becomes flattened and broader towards the sides and rear, measuring up to 3 cm in width. It bears ribs up to 2 mm high and spaced up to 2.5 mm apart. These ribs terminate in teeth (≤8 mm long) on the inner margin of the peristome, the largest being located towards the top. There is often a gap of several millimetres separating the two lobes of the peristome directly below the lid. The pitcher lid or operculum
Operculum (botany)
An operculum, in botany, is a term generally used to describe a structure within a plant, moss, or fungus acting as a cap, flap, or lid. In plants, it may also be called a bud cap.Examples of structures identified as opercula include:...
is ovate to orbicular and typically has a cordate base as well as a frilled margin. It measures up to 6 cm in length by 4.5 cm in width. A triangular or hook-shaped basal crest (≤1 cm long) is commonly present on the lower surface of the lid. An unbranched spur measuring up to 10 mm in length is inserted near the base of the lid. Lower pitchers typically have a very dark pigmentation, being purplish-black throughout. However, 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...
covering the traps can give them an orange or brownish sheen. The peristome is generally purple, black, or dark brown, but may have lighter coloured teeth ranging from green, through yellow, to white. The inner surface of the pitcher may be light yellow, white, or light purple, and often bears purple speckles. The pitcher lid is often yellow or green on the underside and dark purple on its upper surface. Occasionally, the pitcher may be yellowish-green throughout with a black peristome.
Upper pitchers are narrowly infundibular in the basal third to half of the pitcher cup and cylindrical above. A constriction and associated hip often delimit these two parts. Aerial traps are smaller than their terrerstrial counterparts, reaching 20 cm in height by 4 cm in width. In upper pitchers, the wings are reduced to ribs. The peristome, which reaches up to 8 mm in width, is cylindrical and expanded at the sides and rear. It bears ribs up to 0.5 mm high and spaced up to 0.5 mm apart as well as teeth up to 1.5 mm long. The pitcher lid is sub-orbicular to slightly ovate and has a cordate base. It measures up to 4.5 cm in length by 4 cm in width. It may or may not bear an appendage on its underside. The spur is simple or branched and attains a length of 5 mm. Upper pitchers exhibit a similar pigmentation to lower pitchers, but are typically lighter.
Nepenthes izumiae 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 18 cm long, 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...
constitutes up to 10 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 8 cm. Flowers are borne solitarily 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....
(≤5 mm long) that lack bract
Bract
In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis, or cone scale. Bracts are often different from foliage leaves. They may be smaller, larger, or of a different color, shape, or texture...
s. 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 ovate and up to 6 mm long. Fruit
Fruit
In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...
s reach 15 mm in length. The structure of the male inflorescence has not been documented.
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 red, brown or white hairs up to 1 mm long may be present on the laminar margins, pitchers (particularly lower ones), tendrils, and parts of the inflorescence.
Ecology
Nepenthes izumiae has only been recorded from two peaks north of BukittinggiBukittinggi
Bukittinggi is one of the larger cities in West Sumatra, Indonesia, with a population of over 91,000 people and an area of 25.24 km². It is situated in the Minangkabau highlands, 90 km by road from the West Sumatran capital city of Padang. It is located at , near the volcanoes Mount...
in the Barisan Mountains
Barisan Mountains
The Bukit Barisan or the Barisan Mountains are a mountain range on the western side of Sumatra, Indonesia, covering nearly 1,700 km from the north to the south of the island. The Bukit Barisan range consists primarily of volcanoes shrouded in dense jungle cover, including Sumatran tropical pine...
of West Sumatra
West Sumatra
West Sumatra is a province of Indonesia. It lies on the west coast of the island Sumatra. It borders the provinces of North Sumatra to the north, Riau and Jambi to the east, and Bengkulu to the southeast. It includes the Mentawai Islands off the coast...
, Indonesia
Indonesia
Indonesia , officially the Republic of Indonesia , is a country in Southeast Asia and Oceania. Indonesia is an archipelago comprising approximately 13,000 islands. It has 33 provinces with over 238 million people, and is the world's fourth most populous country. Indonesia is a republic, with an...
. In the interests of conservation, the exact locality was not disclosed in the formal description. The species has an altitudinal range of 1700–1900 m above sea level.
The typical habitat of N. izumiae is upper montane mossy forest, where conditions are moist and the plants experience diffused sunlight. At one location, the vegetation is dominated by fern
Fern
A fern is any one of a group of about 12,000 species of plants belonging to the botanical group known as Pteridophyta. Unlike mosses, they have xylem and phloem . They have stems, leaves, and roots like other vascular plants...
s of the genera
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...
Dicranopteris and Dipteris. The species is most commonly epiphytic
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...
, often being found on moss
Moss
Mosses are small, soft plants that are typically 1–10 cm tall, though some species are much larger. They commonly grow close together in clumps or mats in damp or shady locations. They do not have flowers or seeds, and their simple leaves cover the thin wiry stems...
-covered branches, but it can also grow terrestrially over a layer of moss. Nepenthes izumiae is naturally sympatric
Sympatry
In biology, two species or populations are considered sympatric when they exist in the same geographic area and thus regularly encounter one another. An initially-interbreeding population that splits into two or more distinct species sharing a common range exemplifies sympatric speciation...
with N. dubia
Nepenthes dubia
Nepenthes dubia is a tropical pitcher plant endemic to Sumatra. The specific epithet dubia is the Latin word for "doubtful".-Botanical history:...
and N. gymnamphora
Nepenthes gymnamphora
Nepenthes gymnamphora is a tropical pitcher plant native to the Indonesian islands of Java and Sumatra. There is much debate surrounding the taxonomic status of this species and the taxa N. pectinata and N. xiphioides....
, and a natural hybrid with the former has been recorded.
The only known populations of N. izumiae lie outside the boundaries of national park
National park
A national park is a reserve of natural, semi-natural, or developed land that a sovereign state declares or owns. Although individual nations designate their own national parks differently A national park is a reserve of natural, semi-natural, or developed land that a sovereign state declares or...
s. 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....
considers the species to be "at significant risk of being poached and over collected" and cites the "rapid demise" of N. aristolochioides
Nepenthes aristolochioides
Nepenthes aristolochioides is a tropical pitcher plant endemic to Sumatra, where it grows at elevations of 1800–2500 m above sea level. It has an extremely unusual pitcher morphology, having an almost vertical opening to its traps....
, another highly sought-after Sumatran plant, as an example of the possible fate of this species. Nepenthes izumiae is also threatened by forest and shrub fires as well as land development.
Related species
Nepenthes izumiae is thought to be most closely allied to two other Sumatran endemics: N. lingulataNepenthes lingulata
Nepenthes lingulata is a tropical pitcher plant endemic to northern Sumatra. The species is characterised by the highly developed appendage present on the underside of the lid...
and N. singalana
Nepenthes singalana
Nepenthes singalana is a highland Nepenthes pitcher plant species native to the island of Sumatra. It is most closely related to N. diatas and N. spathulata.-Taxonomy:...
.
With the former, N. izumiae shares the general morphology and colouration of its pitchers. However, it can be easily distinguished from that species as it lacks the highly developed filiform appendage that gives N. lingulata its name. It also differs in typically having an orbicular lid, as opposed to the triangular lid of N. lingulata, as well as broader pitchers with more highly developed peristome ribs and 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...
. In addition, N. lingulata completely lacks nectar glands on the underside of the lid and has a very dense woolly 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...
.
Nepenthes izumiae differs from N. singalana in that it often possesses a basal crest on the underside of the lid; this structure is never found in N. singalana. Nepenthes izumiae also differs in several other vegetative features: it has broader laminae with persistent hairs on the margins, longer and narrower terrestrial traps, and a thinner peristome with finer ribs and teeth. In addition, whereas N. izumiae is typically epiphytic
Epiphyte
An epiphyte is a plant that grows upon another plant non-parasitically or sometimes upon some other object , derives its moisture and nutrients from the air and rain and sometimes from debris accumulating around it, and is found in the temperate zone and in the...
in growth habit, N. singalana is mostly terrestrial.
Nepenthes izumiae may also bear a resemblance to N. bongso
Nepenthes bongso
Nepenthes bongso is a tropical pitcher plant endemic to Sumatra, where it has an altitudinal distribution of 1000–2700 m above sea level. The specific epithet bongso refers to the Indonesian legend of Putri Bungsu , the spirit guardian of Mount Marapi.The species was formally described by Pieter...
and N. ovata
Nepenthes ovata
Nepenthes ovata is a tropical pitcher plant endemic to Sumatra. The specific epithet ovata is Latin for "ovate" and refers to the shape of the lower pitchers.-Botanical history:...
, but both of these species have entirely infundibular upper pitchers and often have spathulate laminae with glabrous margins. Nepenthes spathulata
Nepenthes spathulata
Nepenthes spathulata is a tropical pitcher plant native to Java and Sumatra, where it grows at elevations of between 1100 and 2900 m above sea level. The specific epithet spathulata is derived from the Latin word spathulatus, meaning "spatula shaped", and refers to the shape of the...
could also be confused with N. izumiae, but it can be distinguished on the basis of its wider laminae and pitchers, the latter typically also being lighter in colouration.
Natural hybrids
In the wild, N. izumiae is known to form natural hybrids with N. dubiaNepenthes dubia
Nepenthes dubia is a tropical pitcher plant endemic to Sumatra. The specific epithet dubia is the Latin word for "doubtful".-Botanical history:...
and N. jacquelineae
Nepenthes jacquelineae
Nepenthes jacquelineae is a tropical pitcher plant endemic to Sumatra. Due to its unique pitcher morphology, it is considered to be one of the most spectacular Nepenthes species native to the island.-Botanical history:...
.
A single mature female plant of N. dubia × N. izumiae grows along the summit trail on Mount Talakmau
Mount Talakmau
Talakmau is a volcano in West Sumatra, Indonesia. Its elevation is 2,919 m .-External links :*...
. It produces infundibular upper pitchers that are yellowish-green in colouration. The pitchers are relatively small, reaching only around 10 cm in height. As in N. dubia, the stem and tendrils are purplish-red. The lamina is green with a red midrib. Nepenthes dubia × N. izumiae differs most obviously from N. dubia in having an ovate lid that is never reflexed beyond 180 degrees. This hybrid is listed as N. dubia × N. singalana in 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...
's 2001 monograph, Nepenthes of Sumatra and Peninsular Malaysia
Nepenthes of Sumatra and Peninsular Malaysia
Nepenthes of Sumatra and Peninsular Malaysia is a monograph by Charles Clarke on the tropical pitcher plants of Sumatra, Peninsular Malaysia, and their minor surrounding islands. It was published in 2001 by Natural History Publications...
, because at the time of its publication it was uncertain whether N. izumiae represented a distinct species.