Nepenthes bicalcarata
3790439
219705167
2008-06-16T14:27:55Z
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robot Adding: [[it:Nepenthes bicalcarata]]
{{Taxobox
| name = ''Nepenthes bicalcarata''
| status = VU
| status_system = iucn2.3
| image = Nepenthesbicalcarata1.jpg
| image_width = 200px
| image_caption = Intermediate pitcher of ''N. bicalcarata''
| regnum = [[Plant]]ae
| divisio = [[Magnoliophyta]]
| classis = [[Magnoliopsida]]
| ordo = [[Caryophyllales]]
| familia = [[Nepenthaceae]]
| genus = ''[[Nepenthes]]''
| species = '''''N. bicalcarata'''''
| binomial = ''Nepenthes bicalcarata''
| binomial_authority = [[Joseph Dalton Hooker|Hook.f.]] (1873)
| synonyms =
*''Nepenthes dyak''<br><small>[[Spencer Le Marchant Moore|S.Moore]] (1880)</small>
}}
'''''Nepenthes bicalcarata''''' ({{pronEng|nəˈpɛnθiːz baɪkælkərɑːtə/ or /bɪkælkərɑːtə}}, [[Latin]]: ''bi'' = two, ''calcaratus'' = spur), also known as the '''Fanged Pitcher-Plant''',<ref name=P&L>Phillipps, A. & A. Lamb 1996. ''Pitcher-Plants of Borneo''. Natural History Publications (Borneo), Kota Kinabalu.</ref> is a tropical [[pitcher plant]] [[endemism|endemic]] to northwestern [[Borneo]].
{{TOClimit|limit=2}}
==Botanical history==
[[Image:Nepenthes bicalcarata Macfarlane illustration.jpg|thumb|left|Illustration of ''N. bicalcarata'' from [[John Muirhead Macfarlane|Macfarlane]]'s 1908 monograph]]
''N. bicalcarata'' was formally described by [[Joseph Dalton Hooker]] in 1873, based on specimens collected by [[Hugh Low]] and [[Odoardo Beccari]] near [[Lawas River]] in Borneo.<ref>Hooker, J.D. 1873. Nepenthaceae. In: A. De Candolle ''Prodromus systematis universalis regni vegetabilis'' '''17''': 90–105.</ref> The [[type specimen]], ''Low s.n.'', is deposited at the [[Royal Botanic Gardens, Kew]].<ref name=Schlauer>Schlauer, J. 2006. [http://www.omnisterra.com/bot/cp_home.cgi?name=bicalcarata&search=all ''Nepenthes bicalcarata'']. Carnivorous Plant Database.</ref> Seven years later, [[Spencer Le Marchant Moore]] described ''Nepenthes dyak'', based on a specimen collected by [[Johannes Elias Teijsmann]], ''Teijsmann 10962'', from [[Kapuas River]] near [[Sintang]] in western Borneo.<ref>Moore, S.L.M. 1880. Alabastra diversa. ''The Journal of Botany'' '''18''': 1–8.</ref><ref name=J&C>Jebb, M.H.P. & M.R. Cheek 1997. A Skeletal Revision of ''Nepenthes'' (Nepenthaceae). ''Blumea'' '''42''' (1): 1–106.</ref> This specimen is also held at the Royal Botanic Gardens, Kew<ref name=Schlauer /> and a duplicate is deposited at the [[National Herbarium of the Netherlands]] in [[Leiden]].<ref>[http://145.18.162.53:81/c8?ent=300017&rec=48918&sct=1 Specimen detail: ''Teijsmann 10962'']. Nationaal Herbarium Nederland.</ref> ''N. dyak'' was later mentioned several more times in the literature,<ref>Burbidge, F.W. 1882. Notes on the new ''Nepenthes''. ''The Gardeners' Chronicle'' '''17'''(1): 56.</ref><ref>Beccari, O. 1896. Malesia, III (1886–1890): Rivista delle specie del genere ''Nepenthes'', p. 1–15.</ref> but is now considered conspecific with ''N. bicalcarta''.<ref name=Clarke />
''N. bicalcarata'' was introduced to Europe in 1879 by British explorer [[Frederick William Burbidge]], who collected plants for the famous [[Veitch Nursery]]. These were cultivated to larger size and distributed in 1881.<ref name=P&L />
During this time, interest in ''Nepenthes'' had reached its peak. A note in ''[[The Gardeners' Chronicle]]'' of 1881 mentions the Veitch Nursery's ''N. bicalcarata'' as follows:<ref>[Anonymous] 1881. Messr's Veitch's Nepenthes House. ''The Gardeners' Chronicle'' n. ser. '''16''': 598.</ref>
<blockquote>"Then there is ''N. bicalcarata'', a most robust habited kind with sturdy foliage and bag-like pitchers provided with a vicious-looking rat-trap-like apparatus in its lid which renders it very distinct from its neighbours."</blockquote>
Several years after its introduction, ''N. bicalcarata'' was still very much a horticultural rarity. In Veitch's catalogue for 1889, ''N. bicalcarata'' was priced at [[Pound sterling|£]]3.3[[shilling|s]] per plant, while the famous giant-pitchered ''[[Nepenthes northiana|N. northiana]]'' and ''[[Nepenthes rajah|N. rajah]]'' were selling for £2.2s.<ref name=P&L />
==Description==
''N. bicalcarata'' plants are the largest in the genus, climbing up to 20 m into the forest [[Canopy (forest)|canopy]]. The cylindrical stem is thicker than that of any other ''Nepenthes'' species, measuring up to 3.5 cm in diameter. [[Internode]]s are up to 40 cm long.<ref name=Clarke>Clarke, C.M. 1997. ''Nepenthes of Borneo''. Natural History Publications (Borneo), Kota Kinabalu.</ref><ref name=Steiner>Steiner, H. 2002. ''Borneo: Its Mountains and Lowlands with their Pitcher Plants''. Toihaan Publishing Company, Kota Kinabalu.</ref>
[[Image:Nepenthesbicalcarata5.jpg|thumb|left|Climbing plant with upper pitchers]]
The leaves of ''N. bicalcarata'' are [[wikt:petiolate|petiolate]] and [[wikt:coriaceous|coriaceous]] in texture. The [[wikt:lamina|lamina]] is [[wikt:obovate|obovate]]-[[wikt:lanceolate|lanceolate]] in form and also reaches huge dimensions, growing to 80 cm in length and 12 cm in width.<ref>Danser, B.H. 1928. The Nepenthaceae of the Netherlands Indies. ''Bulletin de Jardin de Botanique, Buitenzorg'', Série III, '''9'''(3–4): 249–438.</ref> It is slightly [[wikt:decurrent|decurrent]] on the stem, forming two narrow wings. The lamina has indistinct longitudinal veins and numerous [[wikt:pennate|pennate]] veins. [[Tendril]]s may be up to 60 cm long and 8 mm wide. They are hollow and swollen near the pitcher.<ref name=Clarke />
[[Image:Nepenthesbicalcarata6.jpg|thumb|Lower pitchers]]
Although most parts of the plant are very large, the pitchers themselves do not rival those of species such as ''[[Nepenthes rajah|N. rajah]]''. Nevertheless, they may have a volume of over one litre and grow up to 25 cm high and 16 cm wide. The two sharp spines for which the species is famous are present on the underside of the pitcher lid, and may be 3 cm long. A pair of prominent fringed wings (≤15 mm wide) run down the front of lower pitchers. These are usually reduced to ribs in aerial pitchers. The [[peristome]] (≤20 mm wide) is characteristically flattened and curved inwards. It bears small but distinct teeth. The pitcher lid or [[Operculum (botany)|operculum]] is [[wikt:reniform|reniform]] to [[wikt:cordate|cordate]] and has no appendages. An unbranched [[Spur (biology)|spur]] (≤15 mm long) is inserted at the base of the lid.<ref name=Clarke />
''N. bicalcarata'' has a [[panicle|paniculate]] [[inflorescence]]. The [[peduncle]] may be up to 40 cm long and the [[rachis]] can reach 100 cm in length. Female inflorescences are usually shorter.<ref>Macfarlane, J.M. 1908. Nepenthaceae. In: A. Engler ''Das Pflanzenreich IV'', III, Heft 36: 1–91.</ref> Branches on the flower stem are up to 40 mm long and bear up to 15 flowers. [[Sepal]]s are either [[wikt:obovate|obovate]] or [[wikt:lanceolate|lanceolate]] and up to 4 mm long.<ref name=Clarke />
Mature plants are virtually [[wikt:glabrous|glabrous]]. [[wikt:caducous|Caducous]] hairs are present on the youngest parts of the plant and on the inflorescences.
''N. bicalcarata'' varies little across its range. Consequently, no [[infraspecific taxon|infraspecific taxa]] have been described.<ref name=Clarke />
==Ecology and conservation status==
[[Image:Headhunter's trail Mulu N. bicalcarata 3.jpg|thumb|220px|Natural habitat of ''N. bicalcarata'']]
''N. bicalcarata'' is [[endemism|endemic]] to [[Borneo]]. It is most common in the [[peat swamp]] forests of the western coast of the island, which stretch across [[Sarawak]], [[Sabah]], [[Kalimantan]], and [[Brunei]]. There it often grows in the shade of the ubiquitous [[dipterocarp]] ''[[Shorea albida]]''.<ref name=P&L /> ''N. bicalcarata'' also occurs in [[kerangas forest|''kerangas'' forest]] and has even been recorded from white sand [[heath forest]]s in [[Sarawak]] and [[East Kalimantan]].<ref name=P&L /> The species is often [[sympatric]] with ''[[Nepenthes ampullaria|N. ampullaria]]'' in these habitats.<ref name=Clarke />
Specimens growing in undisturbed peat swamp forest, where sunlight is greatly diffused and high humidity prevails, reach the largest dimensions.<ref name=Clarke /> ''N. bicalcarata'' has a shallow root system that only penetrates the top layer of [[peat]] and [[leaf litter]], to a depth of about 25 cm. Below this, high concentrations of [[tannin]]s and [[alkaloid]]s render the substrate toxic.<ref name=P&L />
''N. bicalcarata'' is generally found below 300 m in altitude, although H. Hallier reported a single collection in 1894 from between 700 and 950 m above sea level.<ref>Hallier, H. 1895. Ein neues ''Cypripedium'' aus Borneo. ''Natuurkundig Tijdschrift voor Nederlandsch Indië'' LIV: 450–452.</ref>
The [[conservation status]] of ''N. bicalcarata'' is listed as [[Vulnerable species|Vulnerable]] on the [[IUCN Red List|2006 IUCN Red List of Threatened Species]] based on an assessment carried out in 2000.<ref>Schnell, D., P. Catling, G. Folkerts, C. Frost, R. Gardner, ''et al.'' 2000. [http://www.iucnredlist.org/search/details.php/39624/all ''Nepenthes bicalcarata'']. ''2006 [[IUCN Red List|IUCN Red List of Threatened Species]]''. [[World Conservation Union|IUCN]] 2006. Retrieved on 11 May 2006. Listed as Vulnerable (VU B1+2c v2.3).</ref> In 1997, [[Charles Clarke (botanist)|Charles Clarke]] informally classified the species as [[Near Threatened]] based on the [[World Conservation Union|IUCN]] criteria.<ref name=Clarke /> This agrees with the conservation status assigned to ''N. bicalcarata'' by the [[World Conservation Monitoring Centre]].<ref>Simpson, R.B. 1995. ''Nepenthes'' and Conservation. ''Curtis's Botanical Magazine'' '''12''': 111–118.</ref>
==Carnivory==
[[Image:Serian road side N. bicalcarata 2.jpg|thumb|Upper pitcher with prominent thorns]]
The two thorns that give ''N. bicalcarata'' its name are unique to this species and bear some of the largest [[nectar]] [[gland]]s in the plant kingdom.<ref>Clarke, C.M. 2001. ''A Guide to the Pitcher Plants of Sabah''. Natural History Publications (Borneo), Kota Kinabalu.</ref><ref name=C&L>Clarke, C.M. & C.C. Lee 2004. ''Pitcher Plants of Sarawak''. Natural History Publications (Borneo), Kota Kinabalu.</ref> The purpose of these structures has long been debated among botanists. [[Frederick William Burbidge]] suggested that they might serve to deter [[arboreal]] [[mammal]]s such as [[tarsier]]s, [[loris]]es and [[monkey]]s from stealing the contents of the pitchers. In an article published in 1982, Cliff Dodd speculated on the function of the thorns, but did not believe they play a role in prey capture.<ref name=Dodd>Dodd, C. 1982. {{PDFlink|[http://www.carnivorousplants.org/cpn/articles/CPNv11n3p64_65_73_78.pdf The Most Dangerous (Looking) ''Nepenthes''.]|658 [[Kibibyte|KiB]]<!-- application/pdf, 674130 bytes -->}} ''[[Carnivorous Plant Newsletter]]'' '''11'''(3): 64–65, 73, 78.</ref> [[Charles Clarke (botanist)|Charles Clarke]] observed that monkeys and tarsiers rip the pitchers open at the sides in order to feed from them, rather than reaching in through the pitcher mouth.<ref name=thorns>Clarke, C.[M.] 1993. {{PDFlink|[http://www.carnivorousplants.org/cpn/articles/CPNv22n1_2p27_28.pdf The Possible Functions of the Thorns of ''Nepenthes bicalcarata'' (Hook.f.) Pitchers.]|194 [[Kibibyte|KiB]]<!-- application/pdf, 199215 bytes -->}} ''[[Carnivorous Plant Newsletter]]'' '''22'''(1–2): 27–28.</ref> However, he found that the mammals attacked the pitchers of ''N. bicalcarata'' less frequently than those of other species, such as ''[[Nepenthes rafflesiana|N. rafflesiana]]''.<ref name=thorns /> Clarke's observations suggest that the spines likely serve to lure insects into a precarious position over the pitcher mouth, where they may lose their footing and fall into the pitcher fluid, eventually drowning.<ref name=thorns />
A similar trapping method is employed by the [[Sumatra]]n endemic ''[[Nepenthes lingulata|N. lingulata]]'', which has a single [[wikt:filiform|filiform]] appendage positioned over the pitcher mouth. However, in that species the appendage is a structure of the lid and not the peristome.<ref name=lingulata>Lee, C.C., Hernawati & P. Akhriadi 2006. [http://www.ingentaconnect.com/content/nhn/blumea/2006/00000051/00000003/art00007 Two new species of ''Nepenthes'' (Nepenthaceae) from North Sumatra]. ''Blumea'' '''51'''(3): 561–568.</ref>
Together with ''[[Nepenthes ampullaria|N. ampullaria]]'' and ''[[Nepenthes ventricosa|N. ventricosa]]'', ''N. bicalcarata'' is unusual in that the glandular region of the pitcher extends almost to the peristome, such that there is little or no conductive waxy zone.<ref name=Bohn>Bohn, H.F. & W. Federle 2004. {{PDFlink|[http://www.pnas.org/cgi/reprint/101/39/14138.pdf Insect aquaplaning: ''Nepenthes'' pitcher plants capture prey with the peristome, a fully wettable water-lubricated anisotropic surface.]}} ''[[Proceedings of the National Academy of Sciences]]'' '''101'''(39): 14138–14143.</ref> The waxy zone functions by causing prey to slip and fall into the digestive fluid. A 2004 study found that the peristome of ''N. bicalcarata'' plays a very important role in prey capture. When it is dry, the peristome is very ineffective in catching insect prey, but when wetted, the capture rate increases more than three-fold.<ref name=Bohn />
A 1999 study of pitcher morphology and spectral reflectance characteristics showed that ''N. bicalcarata'' has no colour contrast maximum between the peristome and pitcher cup in the [[ultraviolet]] waveband, but small maxima of –0.17 at 450 nm ([[Violet (color)|violet]]), 0.32 at 548 nm ([[green]]), and –0.16 at 668 nm ([[red]]).<ref name=spectrum>Moran, J.A., W.E. Booth & J.K. Charles 1999. {{PDFlink|[http://aob.oxfordjournals.org/cgi/reprint/83/5/521.pdf Aspects of Pitcher Morphology and Spectral Characteristics of Six Bornean ''Nepenthes'' Pitcher Plant Species: Implications for Prey Capture.]}} ''Annals of Botany'' '''83''': 521–528.</ref> This means that the peristome is less reflective than the pitcher cup in the violet and red bands, but more reflective in the green band. The contrast maxima in the green and blue regions seem to correspond to insect visual sensitivity maxima, while the others do not.<ref name=spectrum /> Based on their findings, the authors made the "tentative prediction" that the upper pitchers of ''N. bicalcarata'' are less successful at catching anthophilous (flower-visiting) prey than those of sympatric ''N. rafflesiana''.<ref name=spectrum />
==Association with ants==
''N. bicalcarata'' plays host to an unusual species of [[ant]] that makes its nest in the plant's hollow tendrils.<ref name=Clarke /><ref>Shelford, R. 1916. ''A naturalist in Borneo''. T. Fisher Unwin, London.</ref><ref>Cresswell, J.E. 2000. Resource input and the community structure of larval infaunas of an eastern tropical pitcher plant ''Nepenthes bicalcarata''. ''Ecological Entomology'' '''25'''(3): 362–366. {{DOI|10.1046/j.1365-2311.2000.00267.x}}</ref><ref>Merbach, M.A., G. Zizka, B. Fiala, U. Maschwitz & W.E. Booth 2000. Carnivory and myrmecophytism—a contradiction? Studies on ''Nepenthes bicalcarata'' Hook.f. and its ants. Tagungsband gtö 2000 13. Jahrestagung der Deutschen Gesellschaft für Tropenökologie 1–3. March 2000 in Würzburg Lehrstuhl für Tierökologie und Tropenbiologie Universität Würzburg. p. 106.</ref> Described as ''[[Camponotus schmitzi]]'' in 1933,<ref>Schuitemaker, J.P. & A. Stärke 1933. Contribution a l'etude de la faune Nepenthicole. Art. III Un noveau ''Camponotus'' de Borneo, habitant les tiges cruises de ''Nepenthes'' récolté par J. P. Schuitemaker et décrit par A. Stärke, den Dolder. ''Overdruk uit het Natuurhistorisch Maandblad'' '''22'''(3): 29–31.</ref> it is a member of the extremely populous and widespread genus of [[carpenter ant]]s.
[[Image:Bicalcarata-upperpitcher.jpg|thumb|left|Upper pitcher with swollen tendril colonised by ''Camponotus schmitzi''.]]
This unique animal-plant interaction was noted by [[Frederick William Burbidge]] as early as 1880.<ref>Burbidge, F.W. 1880. ''The Gardens of the Sun''. Murray, London. 364 pp.</ref> In 1904, [[Odoardo Beccari]] suggested that the ants feed on insects found on and around the plant, but may fall prey to it themselves.<ref>Beccari, O. 1904. ''Wanderings in the great forests of Borneo''. Archibald and Constable, London.</ref> In 1990, B. Hölldobler and E.O. Wilson proposed that ''N. bicalcarata'' and ''C. schmitzi'' form a [[mutualism|mutually beneficial]] association.<ref>Hölldobler, B. & E.O. Wilson 1990. ''The Ants''. Springer-Verlag, Berlin, Germany.</ref> At the time, however, no experimental data existed to support such a hypothesis. A series of observations and experiments carried out in [[Brunei]] by [[Charles Clarke (botanist)|Charles Clarke]] in 1992 and 1998,<ref>Clarke, C.M. 1992. The ecology of metazoan communities in ''Nepenthes'' pitcher plants in Borneo, with special reference to the community of ''Nepenthes bicalcarata'' Hook.f. Ph.D. thesis, University of New England, Armidale, New South Wales. 269 pp.</ref><ref>Clarke, C.M. 1998. Initial colonisation and prey capture in ''Nepenthes bicalcarata'' (Nepenthaceae) pitchers in Brunei. ''Sandakania'' '''12''': 27–36.</ref><ref>Clarke, C.M. 1998. The aquatic arthropod community of the pitcher plant, ''Nepenthes bicalcarata'' (Nepenthaceae) in Brunei. ''Sandakania'' '''11''': 55–60.</ref> and by Clarke and Kitching in 1993 and 1995,<ref>Clarke, C.M. & R.L. Kitching 1993. The Metazoan Food Webs from Six Bornean ''Nepenthes'' Species. ''Ecological Entomology'' '''18''': 7–16.</ref><ref>Clarke, C.M. & R.L. Kitching 1995. Swimming Ants and Pitcher Plants: a Unique Ant-Plant Interaction from Borneo. ''Journal of Tropical Ecology'' '''11'''(4): 589–602.</ref> strongly support the [[mutualism]] theory.
The ants feed by descending into the pitcher fluid and retrieving [[arthropod]]s caught by the plant. The ants seem to ignore smaller insects and only target larger prey items. Hauling food from the pitcher fluid to the peristome, a distance of no more than 5 cm, may take up to 12 hours.<ref name=Clarke /> In this way the contents of ''N. bicalcarata'' pitchers is controlled such that organic matter does not accumulate to the point of [[putrefaction]], which can lead to the demise of [[nepenthes infauna|pitcher infauna]] (which also appear to benefit the plant) and sometimes the pitcher itself.<ref name=Clarke /><ref>Hansen, E. 2001. [http://discovermagazine.com/2001/oct/featplants Where rocks sing, ants swim, and plants eat animals: finding members of the ''Nepenthes'' carnivorous plant family in Borneo]. ''Discover'' '''22'''(10): 60–68.</ref>
Research conducted by Dennis and Marlis Merbach has shown that ''C. schmitzi'' protect ''N. bicalcarata'' against pitcher-destroying [[weevil]]s of the genus ''[[Alcidodes]]''.<ref>Merbach, M.A., G. Zizka, B. Fiala, D.J. Merbach, W.E. Booth & U. Maschwitz 2007. Why a carnivorous plant cooperates with an ant:- selective defense against pitcher-destroying weevils in the myrmecophytic pitcher plant ''Nepenthes bicalcarata'' Hook.f.. ''Ecotropica'' '''13''': 45–56.</ref><ref>Merbach, M.A. & D.J. Merbach 2002. {{PDFlink|[http://www.muk.uni-frankfurt.de/Publikationen/FFFM/dok/2002/2002-3/Fleischfressende-Kannenpflanze_74-77.pdf Auf der Suche nach Nahrung in die Todesfalle.]|116 [[Kibibyte|KiB]]<!-- application/pdf, 119690 bytes -->}} ''Forschung Frankfurt'' 2002(3): 74–77.</ref>
The ants seem to favour upper pitchers and rarely colonise lower pitchers.<ref>Clarke, C.M. 1997. The effects of pitcher dimorphism on the metazoan community of the carnivorous pitcher plant ''Nepenthes bicalcarata'' Hook.f.. ''Malayan Nature Journal'' '''50''': 149–157.</ref> This is likely due to the fact that terrestrial traps are periodically submerged in water during heavy rains. Flooding of the ants' nest chamber could result in the death of the developing eggs, [[larva]]e, and [[pupa]]e.<ref name=C&L />
''C. schmitzi'' nests solely in the tendrils of ''N. bicalcarata'' and rarely ventures onto other plants. The species is completely dependent on ''N. bicalcarata'' for food and [[wikt:domicile|domicile]].<ref name=Clarke /> ''N. bicalcarata'', on the other hand, is able to survive and reproduce without the presence of the ants; it is a [[Mutualism|facultative mutualist]]. This being the case, there appear to be few mature plants over 2 metres in height not colonised by ''C. schmitzi''.<ref name=Clarke />
John Thompson suggests that ''N. bicalcarata'' may be the only plant species that obtains nutrients through both insect capture and ant-hosting habits.<ref>Thompson, J.H. 1981. Reverse animal-plant interactions: the evolution of insectivorous and ant-fed plants. ''Biological Journal of the Linnean Society'' '''16''': 147–155.</ref>
A species of [[mite]], ''[[Naiadacarus nepenthicola]]'', appears to be restricted to the pitchers of ''N. bicalcarata''. It is thought to feed on decomposing leaves and insects that are caught in the pitchers. [[Deutonymph]]s of this mite are dispersed through [[phoresy]] on ''C. schmitzi''.<ref>Fashing, N.J. & T.H. Chua 2002. {{PDFlink|[http://njfash.people.wm.edu/naiadacarus%20.pdf Systematics and ecology of ''Naiadacarus nepenthicola'', a new species of Acaridae (Acari : Astigmata) inhabiting the pitchers of ''Nepenthes bicalcarata'' Hook. f. in Brunei Darussalam.]|2.12 [[Mebibyte|MiB]]<!-- application/pdf, 2228189 bytes -->}} ''International Journal of Acarology'' '''28'''(2): 157–167.</ref>
==Natural hybrids==
The following natural [[Hybrid (biology)|hybrids]] involving ''N. bicalcarata'' have been recorded.
*''[[Nepenthes ampullaria|N. ampullaria]]'' × ''N. bicalcarata''<ref name=Clarke />
*(''[[Nepenthes ampullaria|N. ampullaria]]'' × ''[[Nepenthes gracilis|N. gracilis]]'') × ''N. bicalcarata'' [=''[[Nepenthes x trichocarpa|N. × trichocarpa]]'' × ''N. bicalcarata'']
*''N. bicalcarata'' × ''[[Nepenthes gracilis|N. gracilis]]'' [=''[[Nepenthes × cantleyi|N. × cantleyi]]'']<ref name=Clarke />
*''N. bicalcarata'' × [[Nepenthes mirabilis|''N. mirabilis'' var. ''echinostoma'']]<ref name=Clarke />
*''N. bicalcarata'' × ''[[Nepenthes rafflesiana|N. rafflesiana]]''<ref name=Clarke />
*? (''N. bicalcarata'' × ''[[Nepenthes rafflesiana|N. rafflesiana]]'') × [[Nepenthes mirabilis|''N. mirabilis'' var. ''echinostoma'']]<ref name=Clarke />
None of these hybrids are known to be colonised by ''C. schmitzi'' as is the parent species ''N. bicalcarata''.<ref name=Clarke />
===''N. ampullaria'' × ''N. bicalcarata''===
[[Image:Bicalxampul.jpg|thumb|Lower pitcher of ''N. ampullaria'' × ''N. bicalcarata'' (cultivated)]]
Since ''N. ampullaria'' and ''N. bicalcarata'' are often sympatric in the wild, it is not surprising that they occasionally hybridise. Several examples of this natural hybrid are known from [[Brunei]], where it grows in [[peat swamp forest]] and [[heath forest]].<ref name=Clarke /> It was first recorded by [[Mitsuru Hotta]] in 1966.<ref>Hotta, M. 1966. Notes on Bornean Plants. ''Acta Phytotaxonomica et Geobotanica'' '''22'''(1–2): 7–9.</ref>
Pitchers bear the characteristic thorns of ''N. bicalcarata'', although they are greatly reduced in size. The mouth is round and the lid is [[wikt:ovate|ovate]]-[[wikt:cordate|cordate]] in form. This hybrid resembles ''[[Nepenthes x hookeriana|N. × hookeriana]]'' to a certain extent, but differs in having spines on the underside of the lid and more globose upper pitchers with a smaller lid.<ref name=Clarke />
Aerial pitchers of ''N. ampullaria'' × ''N. bicalcarata'' are usually dominated by characteristics of ''N. ampullaria''. They are often very small and unable to function in a normal manner.<ref name=Clarke />
===(''N. ampullaria'' × ''N. gracilis'') × ''N. bicalcarata''===
This rare complex hybrid was discovered in the lowland forests of [[Brunei]]. It produces small speckled pitchers with reduced thorns under the lid. The plant is intermediate in appearance between ''[[Nepenthes x trichocarpa|N. × trichocarpa]]'' and ''N. bicalcarata''.
===''N. bicalcarata'' × ''N. gracilis''===
{{main|Nepenthes × cantleyi}}
[[Image:Nepenthes x cantleyi.jpg|thumb|Lower pitcher of ''Nepenthes × cantleyi'']]
This hybrid has been named ''[[Nepenthes × cantleyi|N. × cantleyi]]'' after [[Rob Cantley]]. The morphology of the pitchers closely resembles ''N. bicalacarata'', although the peristome is more similar to that of ''N. gracilis''. The characteristic spines of ''N. bicalcarata'' are greatly reduced and are only present as small bumps. This hybrid has the growth habit of ''N. gracilis'', with the stem scrambling along the ground. It grows in open, sandy areas. The pitcher fluid is notably [[acid]]ic like that of ''N. gracilis'', with [[pH]] values as low as 1.82 being recorded.<ref name=Clarke />
===''N. bicalcarata'' × ''N. mirabilis'' var. ''echinostoma''===
This natural hybrid is rare and is only known from [[Brunei]], where it involves ''N. mirabilis'' var. ''echinostoma''. It closely resembles ''N. bicalcarata'', although it differs from that species in having reduced thorns and a wider peristome. Unlike ''N. bicalcarata'', this hybrid inhabits open areas with sandy substrates.<ref name=Clarke />
===''N. bicalcarata'' × ''N. rafflesiana''===
This relatively rare natural hybrid is sometimes found growing among populations of ''N. bicalcarata'' and ''N. rafflesiana''. It is intermediate in form between its parent species.
===(''N. bicalcarata'' × ''N. rafflesiana'') × ''N. mirabilis'' var. ''echinostoma''===
[[Charles Clarke (botanist)|Charles Clarke]] reported a single plant displaying characters intermediate in form between ''N. bicalcarata'', ''N. rafflesiana'' and ''N. mirabilis'' var. ''echinostoma'' growing among populations of these species. It is likely a complex hybrid, although this cannot be proven without the use of [[genetic testing]].<ref name=Clarke />
==Cultivation and cultivars==
[[Image:Nepenthes bicalcarata.jpg|thumb|Lower pitcher of a plant cultivated in [[Kuching]], [[Sarawak]].]]
''N. bicalcarata'' may be cultivated in a similar manner to other members of the genus, though it requires relatively hot and humid conditions.<ref>D'Amato, P. 1998. ''The Savage Garden — Cultivating Carnivorous Plants''. Ten Speed Press, Berkley, California.</ref><ref name=Dodd /> It needs large pots to do well, and temporary halts in growth are often due to becoming root-bound. Re-potting to a larger pot will often result in a rapid size increase. Under satisfactory conditions, this plant will grow quite fast for a ''Nepenthes'', reaching a large size relatively rapidly.
Despite naturally occurring in peat swamp forests, ''N. bicalcarata'' has been successfully grown in a completely inorganic substrate consisting of one part each of Seramis clay perls, lava gravel, and Lecaton expanded clay perls.<ref>Rischer, H. 2000. [http://www.carnivorousplants.org/cpn/samples/v29n2p50_53.html Growing ''Nepenthes'' in a Completely Inorganic Substrate]. ''[[Carnivorous Plant Newsletter]]'' '''29'''(2): 50–53.</ref>
''N. bicalcarata'' has been artificially crossed with ''[[Nepenthes hirsuta|N. hirsuta]]''. A particularly robust-pitchered [[cultivar]] of this hybrid was named ''Nepenthes'' 'Hortulanus Otten', in honour of Karel Otten, former curator of the Botanic Garden in [[Ghent]], [[Belgium]].<ref>Cook, D., J.H. Hummer, A. Vogel, O. Gluch & C. Clayton 2004. [http://www.carnivorousplants.org/cpn/Species/v33n1p19_22.html New Cultivars]. ''[[Carnivorous Plant Newsletter]]'' '''33'''(1): 19–22.</ref>
A cultivar of the artificial cross ''N. bicalcarata'' × ''N. × dyeriana'' was registered in 1988 under the name ''Nepenthes'' 'Nina Dodd'. It is named after a relative of Cliff Dodd, who created the hybrid.<ref>Robinson, J.T. 1988. [http://www.carnivorousplants.org/cpn/Species/v17n1p20.html New Cultivars]. ''[[Carnivorous Plant Newsletter]]'' '''17'''(1): 20.</ref>
Two further cultivars of manmade hybrids involving ''N. bicalcarata'' have been named. These are ''Nepenthes'' 'Bella' ((''[[Nepenthes ampullaria|N. ampullaria]]'' × ''N. bicalcarata'') × ''[[Nepenthes truncata|N. truncata]]'') and ''Nepenthes'' 'Rapa' (''N. ampullaria'' × ''N. bicalcarata'').<ref>Fukatsu, Y. 1999. List of ''Nepenthes Hybrids''.</ref> However, both of these names are not established, as they were published without a description.<ref name=Schlauer />
==References==
{{reflist|2}}
==External links==
{{commons}}
*Danser, B.H. 1928. [http://www.omnisterra.com/botany/cp/pictures/nepenthe/dansermg/dans14.htm 4. ''Nepenthes bicalcarata'']. In: The Nepenthaceae of the Netherlands Indies. ''Bulletin de Jardin de Botanique, Buitenzorg'', Série III, '''9'''(3–4): 249–438.
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[[Category:Carnivorous plants of Asia]]
[[Category:Nepenthes]]
[[it:Nepenthes bicalcarata]]
[[lt:Platusis ąsotenis]]
[[zh:二齒豬籠草]]