Nepenthes flava
Encyclopedia
Nepenthes flava is a tropical pitcher plant
endemic to northern Sumatra
, where it grows in montane forest at 1800–2200 m above sea level.
The specific epithet flava is derived from the Latin
word for "yellow" and refers to the typical colouration of the plant's upper pitchers and other vegetative parts.
The species was formally described
by Andreas Wistuba
, Joachim Nerz
and Andreas Fleischmann in an issue of Blumea
published on July 4, 2007. The description was based on cultivated plant material; Wistuba cult. Wistuba 100201 was designated as the holotype
. This specimen was collected at an altitude of 1800 m and is deposited at the National Herbarium of the Netherlands
(L) in Leiden, together with an isotype
. The describing authors explained their choice of the specific epithet flava as follows:
A detailed and slightly modified description of N. flava appeared in Stewart McPherson
's 2009 monograph, Pitcher Plants of the Old World
. Whereas the type description mentions a basal crest on the underside of the lid, McPherson writes that no appendages are present in either lower or upper pitchers.
stage for a short time before transitioning into a scrambling vine
. The stem
, which may be branched, is around 3 mm in diameter and has roughly cylindrical internode
s measuring up to 14 cm in length. The stem ranges in colour from green to dark red.
The lamina (leaf blade) is linear, oblong, or narrowly obovate, and measures up to 9 cm in length by 2.5 cm in width. Its apex is usually acute, but may also be obtuse. The base of the lamina is attenuate and clasps the stem for around half to three-quarters of its circumference. Three prominent longitudinal veins are present on either side of the midrib. Indistinct reticulate veins are also present. The lamina is yellowish-green in colour and the midrib may be reddish. Tendril
s reach 24 cm in length and may be green to red.
Rosette and lower pitchers are either infundibular throughout or ovate and variably inflated. They are small, measuring only up to 7 cm in height by 4 cm in width. A pair of wings (≤3 mm wide) often runs down the upper third of the pitcher's ventral surface, bearing fringe elements around 5 mm long. Occasionally, the wings may be absent altogether. The peristome
varies from cylindrical to slightly expanded and has a wavy outer margin. It is up to 12 mm wide and bears fine ribs up to 0.6 mm high and spaced up to 1 mm apart. On the inner margin of the peristome, these ribs terminate in teeth up to 1.5 mm long, with the largest located towards the rear. The pitcher mouth is round and slightly elongated towards the rear, although it rarely exhibits a neck. The pitcher lid or operculum
is narrowly ovate or elliptic and measures up to 3.5 cm in length by 2 cm in width. On its lower surface, the lid bears a basal gland
ular crest or no appendages at all, as well as numerous circular nectar glands (0.3 mm in diameter), which are concentrated around the midline and crest. An unbranched, filiform spur (≤4 mm long) is inserted near the base of the lid. Unlike their aerial counterparts, lower pitchers vary greatly in pigmentation. The pitcher cup may be yellow, orange, red, or even purple, whereas the inner surface may be light yellow, light orange, or whitish. The peristome is usually darker than the rest of the pitcher, typically being dark orange to purple, although it may be creamy white and occasionally exhibits red stripes. The lid has a similar colour to the pitcher cup, usually having a darker upper surface with dark red speckles.
Upper pitchers are tubular to narrowly infundibular in the lower two-thirds, becoming broadly infundibular above. Characteristically, the hollow pitcher tube often continues past the curved basal portion and for some distance up the tendril. Upper pitchers are similar in size to their terrestrial counterparts, reaching 6 cm in height by 3.5 cm in width. The peristome is flattened and expanded, reaching 15 mm in width. As in lower pitchers, its outer margin is undulate. The peristome ribs are up to 0.2 mm high and spaced up to 0.5 mm apart. The lid is ovate or elliptic and has a somewhat truncate apex. It measures up to 4 cm in length by 2.5 cm in width. A reduced basal crest may be present on the underside of the lid or it may be absent entirely. Other parts are similar to those found in terrestrial traps. Upper pitchers are typically yellow throughout, but some specimens may have a completely red or red-striped peristome and mature traps may be orange or reddish on the upper surface of the lid.
Nepenthes flava has a racemose
inflorescence
up to 15 cm long. Male inflorescences are more floriferous, bearing 15–40 flowers, compared to 15–25 in females. The peduncle
measures up to 4 cm in males and up to 8 cm in females. Flowers are borne solitarily on pedicels
that reach 6 mm in males and 11 mm in females. A basal bract
is often present (≤4 mm long). The nectariferous tepal
s are ovate and measure up to 3 mm in length by 1 mm in width. The androphore is around 3 mm long and terminates in an anther head measuring 1–1.5 mm in diameter. The ovary
is 3–4 mm long. The morphology of the fruit
s and seed
s has not been documented. The inflorescence is yellowish throughout.
All mature vegetative parts are glabrous, but a caducous indumentum
is present on some developing structures. Young parts of the stem bear a sparse covering of reddish-brown, basally branched hairs (0.2–0.5 mm long). A dense indumentum of reddish-brown hairs (0.5–1 mm long) is present on developing pitchers and tendril ends. The inflorescence bears branched, yellowish-brown hairs measuring 0.5–1 mm in length. Tepals have a dense covering of curved, reddish-brown hairs (around 0.2 mm long) along their margins. Ovaries also have a dense covering of reddish-brown hairs, but these are longer, measuring 0.5–1 mm.
of North Sumatra
, Indonesia
. In the interests of conservation, the exact locality has not been disclosed. The species has an altitudinal distribution of 1800–2200 m above sea level.
The typical habitat of N. flava is upper montane mossy forest dominated by Rhododendron
and Leptospermum
plants. It often grows terrestrially in more open areas of forest, where the vegetation rarely exceeds 4–5 m in height. The species is naturally sympatric
with N. mikei
, N. ovata
, N. rhombicaulis
, and N. spectabilis
. Natural hybrids with N. ovata and N. rhombicaulis have been recorded.
The only known locality of N. flava does not lie within the boundaries of a national park
. Although it appears to be locally abundant, 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.
, which also produces highly viscous pitcher fluid.
and N. jacquelineae
. However, it cannot be a natural hybrid between these species as it does not occur sympatrically with them.
The pitchers of N. flava bear a close resemblance to those of N. jacquelineae. Nepenthes flava differs from this species in that its upper pitchers are markedly smaller and have a peristome that is significantly narrower, bears distinct ribs, and has an undulate margin. In addition, the upper pitchers of N. jacquelineae are not known to be yellow throughout, a colouration that is characteristic of N. flava.
With N. inermis, this species shares similarly infundibular pitchers, a narrow lid, and the habit of rapidly transitioning from a rosette to a climbing plant (with associated sudden internode elongation). Furthermore, the seedling pitchers of these two species can appear quite similar. Nepenthes inermis differs most obviously in having upper pitchers that completely lack a peristome and in lacking conspicuous glands on the underside of the lid.
The describing authors considered N. flava to likely represent an evolutionary link between the pair of N. inermis and N. jacquelineae and "common Sumatran species such as N. ovata
". They further speculated:
Other species that produce somewhat similarly shaped upper pitchers include N. eymae
, N. jamban
, N. pitopangii
, N. talangensis
, and N. tenuis
. Nepenthes flava can be distinguished from all of these species on the basis of a combination of features: entirely yellow upper pitchers; a broad, wavy peristome; very small peristome teeth; and a narrowly ovate or elliptic lid that lacks appendages (or has a small basal crest). Furthermore, compared to many of these species, and particularly N. eymae, N. flava is a diminutive plant.
and N. rhombicaulis
. Most of the observed hybrids were young rosette
plants. Although N. flava is also sympatric with N. mikei
and N. spectabilis
, no natural hybrids with these species have been recorded.
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 northern 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 1800–2200 m above sea level.
The specific epithet flava is derived from 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...
word for "yellow" and refers to the typical colouration of the plant's upper pitchers and other vegetative parts.
Botanical history
Nepenthes flava entered cultivation several years prior to being described and was known from at least 2004 under the placeholder name "Nepenthes spec. nov. Sumatra".The species 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 Andreas Wistuba
Andreas Wistuba
Dr. Andreas Wistuba is a German taxonomist and botanist specialising in the carnivorous plant genera Heliamphora and Nepenthes. More than half of all known Heliamphora species have been described by Wistuba.-Publications:...
, Joachim Nerz
Joachim Nerz
Dr. Joachim Nerz is a taxonomist and botanist specialising in the carnivorous plant genera Heliamphora and Nepenthes. Nerz has described several new species, mostly with Andreas Wistuba.-Publications:...
and Andreas Fleischmann in an issue of 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...
published on July 4, 2007. The description was based on cultivated plant material; Wistuba cult. Wistuba 100201 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 at an altitude of 1800 m and is deposited at the National Herbarium of the Netherlands
National Herbarium of the Netherlands
The National Herbarium of the Netherlands was established in 1999 through a decentralized merger of the major university herbaria of Leiden , Utrecht and Wageningen...
(L) in Leiden, together with an isotype
Isotype
Isotype can refer to:* In crystallography, an "isotype" is a synonym for isomorph* In biology, per the International Code of Botanical Nomenclature, the "isotype" is a duplicate of the holotype....
. The describing authors explained their choice of the specific epithet flava as follows:
The specific epithet ‘flava’ refers to the bright yellow colour of the upper pitchers and most of the lower pitchers. Climbing plants especially give the impression of a mainly yellow plant.
A detailed and slightly modified description of N. flava 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...
. Whereas the type description mentions a basal crest on the underside of the lid, McPherson writes that no appendages are present in either lower or upper pitchers.
Description
Nepenthes flava is a climbing plant growing to a height of 6 m. It only remains in the rosetteRosette (botany)
In botany, a rosette is a circular arrangement of leaves, with all the leaves at a single height.Though rosettes usually sit near the soil, their structure is an example of a modified stem.-Function:...
stage for a short time before transitioning into a scrambling vine
Vine
A vine in the narrowest sense is the grapevine , but more generally it can refer to any plant with a growth habit of trailing or scandent, that is to say climbing, stems or runners...
. The stem
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...
, which may be branched, is around 3 mm in diameter and has roughly cylindrical 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 measuring up to 14 cm in length. The stem ranges in colour from green to dark red.
The lamina (leaf blade) is linear, oblong, or narrowly obovate, and measures up to 9 cm in length by 2.5 cm in width. Its apex is usually acute, but may also be obtuse. The base of the lamina is attenuate and clasps the stem for around half to three-quarters of its circumference. Three prominent longitudinal veins are present on either side of the midrib. Indistinct reticulate veins are also present. The lamina is yellowish-green in colour and the midrib may be reddish. 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 reach 24 cm in length and may be green to red.
Rosette and lower pitchers are either infundibular throughout or ovate and variably inflated. They are small, measuring only up to 7 cm in height by 4 cm in width. A pair of wings (≤3 mm wide) often runs down the upper third of the pitcher's ventral surface, bearing fringe elements around 5 mm long. Occasionally, the wings may be absent altogether. 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...
varies from cylindrical to slightly expanded and has a wavy outer margin. It is up to 12 mm wide and bears fine ribs up to 0.6 mm high and spaced up to 1 mm apart. On the inner margin of the peristome, these ribs terminate in teeth up to 1.5 mm long, with the largest located towards the rear. The pitcher mouth is round and slightly elongated towards the rear, although it rarely exhibits a neck. 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 narrowly ovate or elliptic and measures up to 3.5 cm in length by 2 cm in width. On its lower surface, the lid bears a basal gland
Gland
A gland is an organ in an animal's body that synthesizes a substance for release of substances such as hormones or breast milk, often into the bloodstream or into cavities inside the body or its outer surface .- Types :...
ular crest or no appendages at all, as well as numerous circular nectar glands (0.3 mm in diameter), which are concentrated around the midline and crest. An unbranched, filiform spur (≤4 mm long) is inserted near the base of the lid. Unlike their aerial counterparts, lower pitchers vary greatly in pigmentation. The pitcher cup may be yellow, orange, red, or even purple, whereas the inner surface may be light yellow, light orange, or whitish. The peristome is usually darker than the rest of the pitcher, typically being dark orange to purple, although it may be creamy white and occasionally exhibits red stripes. The lid has a similar colour to the pitcher cup, usually having a darker upper surface with dark red speckles.
Upper pitchers are tubular to narrowly infundibular in the lower two-thirds, becoming broadly infundibular above. Characteristically, the hollow pitcher tube often continues past the curved basal portion and for some distance up the tendril. Upper pitchers are similar in size to their terrestrial counterparts, reaching 6 cm in height by 3.5 cm in width. The peristome is flattened and expanded, reaching 15 mm in width. As in lower pitchers, its outer margin is undulate. The peristome ribs are up to 0.2 mm high and spaced up to 0.5 mm apart. The lid is ovate or elliptic and has a somewhat truncate apex. It measures up to 4 cm in length by 2.5 cm in width. A reduced basal crest may be present on the underside of the lid or it may be absent entirely. Other parts are similar to those found in terrestrial traps. Upper pitchers are typically yellow throughout, but some specimens may have a completely red or red-striped peristome and mature traps may be orange or reddish on the upper surface of the lid.
Nepenthes flava 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 15 cm long. Male inflorescences are more floriferous, bearing 15–40 flowers, compared to 15–25 in females. 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...
measures up to 4 cm in males and up to 8 cm in females. 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....
that reach 6 mm in males and 11 mm in females. A basal 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...
is often present (≤4 mm long). The nectariferous 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 measure up to 3 mm in length by 1 mm in width. The androphore is around 3 mm long and terminates in an anther head measuring 1–1.5 mm in diameter. The ovary
Ovary (plants)
In the flowering plants, an ovary is a part of the female reproductive organ of the flower or gynoecium. Specifically, it is the part of the pistil which holds the ovule and is located above or below or at the point of connection with the base of the petals and sepals...
is 3–4 mm long. The morphology of the 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 and 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...
s has not been documented. The inflorescence is yellowish throughout.
All mature vegetative parts are glabrous, but a caducous 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 present on some developing structures. Young parts of the stem bear a sparse covering of reddish-brown, basally branched hairs (0.2–0.5 mm long). A dense indumentum of reddish-brown hairs (0.5–1 mm long) is present on developing pitchers and tendril ends. The inflorescence bears branched, yellowish-brown hairs measuring 0.5–1 mm in length. Tepals have a dense covering of curved, reddish-brown hairs (around 0.2 mm long) along their margins. Ovaries also have a dense covering of reddish-brown hairs, but these are longer, measuring 0.5–1 mm.
Ecology
Nepenthes flava is only known from a single mountain in the Barisan MountainsBarisan 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 North Sumatra
North Sumatra
North Sumatra is a province of Indonesia on the Sumatra island. Its capital is Medan. It is the most populous Indonesian province outside of Java. It is slightly larger than Sri Lanka in area.- Geography and population :...
, 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 has not been disclosed. The species has an altitudinal distribution of 1800–2200 m above sea level.
The typical habitat of N. flava is upper montane mossy forest dominated by Rhododendron
Rhododendron
Rhododendron is a genus of over 1 000 species of woody plants in the heath family, most with showy flowers...
and Leptospermum
Leptospermum
Leptospermum is a genus of about 80-86 species of plants in the myrtle family Myrtaceae. Most species are endemic to Australia, with the greatest diversity in the south of the continent; but one species extends to New Zealand, another to Malaysia, and L. recurvum is endemic to Malaysia.They...
plants. It often grows terrestrially in more open areas of forest, where the vegetation rarely exceeds 4–5 m in height. The species 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. mikei
Nepenthes mikei
Nepenthes mikei is a tropical pitcher plant endemic to Sumatra. It is characterised by its black mottled lower and upper pitchers. The species is closely related to N. angasanensis and N. tobaica....
, 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:...
, N. rhombicaulis
Nepenthes rhombicaulis
Nepenthes rhombicaulis is a tropical pitcher plant endemic to Sumatra. The specific epithet rhombicaulis is formed from the Latin words rhombicus, meaning "rhomboid", and caulis, "stem"...
, and N. spectabilis
Nepenthes spectabilis
Nepenthes spectabilis is a tropical pitcher plant endemic to Sumatra, where it grows at elevations of between 1400 and 2200 m above sea level. The specific epithet spectabilis is Latin for "visible" or "notable".-Botanical history:...
. Natural hybrids with N. ovata and N. rhombicaulis have been recorded.
The only known locality of N. flava does not lie within the boundaries of a 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...
. Although it appears to be locally abundant, 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.
Carnivory
The pitcher fluid of N. flava is highly viscous and coats the inner pitcher walls. This is especially true of aerial traps, which must contend with the action of the wind. The sticky inner walls have been observed to trap small flying insects above the surface of the fluid. The prey subsequently slide down into the fluid where they are digested. It has been suggested that the pitchers of this species function not only as pitfall traps but also as flypaper traps. Indeed, this trapping method is employed by the closely related N. inermisNepenthes inermis
Nepenthes inermis is a tropical pitcher plant endemic to Sumatra. The specific epithet inermis is Latin for "unarmed" and probably refers to the upper pitchers of this species, which are unique in that they completely lack a peristome....
, which also produces highly viscous pitcher fluid.
Related species
Nepenthes flava is thought to be closely related to both N. inermisNepenthes inermis
Nepenthes inermis is a tropical pitcher plant endemic to Sumatra. The specific epithet inermis is Latin for "unarmed" and probably refers to the upper pitchers of this species, which are unique in that they completely lack a peristome....
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:...
. However, it cannot be a natural hybrid between these species as it does not occur sympatrically with them.
The pitchers of N. flava bear a close resemblance to those of N. jacquelineae. Nepenthes flava differs from this species in that its upper pitchers are markedly smaller and have a peristome that is significantly narrower, bears distinct ribs, and has an undulate margin. In addition, the upper pitchers of N. jacquelineae are not known to be yellow throughout, a colouration that is characteristic of N. flava.
With N. inermis, this species shares similarly infundibular pitchers, a narrow lid, and the habit of rapidly transitioning from a rosette to a climbing plant (with associated sudden internode elongation). Furthermore, the seedling pitchers of these two species can appear quite similar. Nepenthes inermis differs most obviously in having upper pitchers that completely lack a peristome and in lacking conspicuous glands on the underside of the lid.
The describing authors considered N. flava to likely represent an evolutionary link between the pair of N. inermis and N. jacquelineae and "common Sumatran species such as 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:...
". They further speculated:
Nepenthes flava might represent an intermediate between N. ovata of northern Sumatra and the unusual N. inermis of the western Sumatran mountains, and would confirm DanserB. H. DanserBenedictus Hubertus Danser , often abbreviated B. H. Danser, was a Dutch taxonomist and botanist...
’s hypothesis in which he united common species familiar to him, i.e. N. bongsoNepenthes bongsoNepenthes 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...
, N. carunculata Danser and N. singalanaNepenthes singalanaNepenthes 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 distinctive species N. inermis and N. dubiaNepenthes dubiaNepenthes dubia is a tropical pitcher plant endemic to Sumatra. The specific epithet dubia is the Latin word for "doubtful".-Botanical history:...
Danser into the subgenus Montanae Danser (Danser, 1928). Nepenthes ovata, N. jacquelineae and others were not known at this time, but it seems likely he would have included them in subgenus Montanae as well.
Other species that produce somewhat similarly shaped upper pitchers include N. eymae
Nepenthes eymae
Nepenthes eymae is a tropical pitcher plant endemic to Sulawesi, where it grows at elevations of 1000–2000 m above sea level. It is very closely related to N. maxima, from which it differs in its wine glass-shaped upper pitchers....
, N. jamban
Nepenthes jamban
Nepenthes jamban is a tropical pitcher plant endemic to northern Sumatra. The specific epithet jamban is the Indonesian word for "toilet" and refers to the shape of the pitchers.-Botanical history:...
, N. pitopangii
Nepenthes pitopangii
Nepenthes pitopangii is a tropical pitcher plant endemic to Lore Lindu National Park in Central Sulawesi, Indonesia. Only a single plant of this species is known and efforts to locate further populations on surrounding mountains have so far been unsuccessful. Nepenthes pitopangii appears to be...
, N. talangensis
Nepenthes talangensis
Nepenthes talangensis is a tropical pitcher plant endemic to Sumatra, where it grows in upper montane forest at elevations of 1800–2500 m above sea level....
, and N. tenuis
Nepenthes tenuis
Nepenthes tenuis is a tropical pitcher plant endemic to Sumatra. The species was first collected in 1957, from a remote mountain in the western part of the island. It remained undescribed until 1994, and was only rediscovered in the wild in 2002. Prior to this, N...
. Nepenthes flava can be distinguished from all of these species on the basis of a combination of features: entirely yellow upper pitchers; a broad, wavy peristome; very small peristome teeth; and a narrowly ovate or elliptic lid that lacks appendages (or has a small basal crest). Furthermore, compared to many of these species, and particularly N. eymae, N. flava is a diminutive plant.
Natural hybrids
Two natural hybrids involving N. flava have been recorded; the describing authors found examples of crosses with N. ovataNepenthes ovata
Nepenthes ovata is a tropical pitcher plant endemic to Sumatra. The specific epithet ovata is Latin for "ovate" and refers to the shape of the lower pitchers.-Botanical history:...
and N. rhombicaulis
Nepenthes rhombicaulis
Nepenthes rhombicaulis is a tropical pitcher plant endemic to Sumatra. The specific epithet rhombicaulis is formed from the Latin words rhombicus, meaning "rhomboid", and caulis, "stem"...
. Most of the observed hybrids were young rosette
Rosette (botany)
In botany, a rosette is a circular arrangement of leaves, with all the leaves at a single height.Though rosettes usually sit near the soil, their structure is an example of a modified stem.-Function:...
plants. Although N. flava is also sympatric with N. mikei
Nepenthes mikei
Nepenthes mikei is a tropical pitcher plant endemic to Sumatra. It is characterised by its black mottled lower and upper pitchers. The species is closely related to N. angasanensis and N. tobaica....
and N. spectabilis
Nepenthes spectabilis
Nepenthes spectabilis is a tropical pitcher plant endemic to Sumatra, where it grows at elevations of between 1400 and 2200 m above sea level. The specific epithet spectabilis is Latin for "visible" or "notable".-Botanical history:...
, no natural hybrids with these species have been recorded.