それぞれの種のIUCNによる公式の保全状況は、レッドリスト最新版から取得した[1]。IUCNの基準に基づいた非公式の保全状況も含まれるが、それらはイタリック体で記載した。特に断りのない限り、分類学上の決定および他のすべての情報は、2009年に出版されたから供給されたスチュワート・マクファーソンの「Pitcher Plants of the Old World」によった[2]。「Pitcher Plants of the Old World」の掲載範囲外である生育分布の標高は他の最新の文献によったため、データの不一致があることを注意する。
Matthew JebbとMartin Cheekは、ウツボカズラ類の研究論文("A skeletal revision of Nepenthes (Nepenthaceae)" (1997) and "Nepenthaceae" (2001))にて3種の交雑種を認証した。最新の文献によると、それらのタクサは一般に種とよりむしろ自然交配として扱っている[2][18][24][25]。3種のうちN. × kinabaluensisは、種として扱うべきとの主張が最も高いが、それらの2大生育地では、親種と推測されている種に依存している[24][87] 。それらの生育地では、何世代にもわたって同じ特徴を示している[24]。Jumaat Haji AdamとC. C. Wilcockは、1998年発表の記事にて、N. × kinabaluensisは、種として認識するよう提唱した[88]。
^Cheek & Jebb (2001) give a range of 780–1880 m for N. boschiana,[24] while Clarke (1997) gives a range of 900–1880 m.[25]
^Cheek & Jebb (2001) give an upper altitudinal limit of 2250 m for N. burbidgeae,[24] while Adam, Wilcock & Swaine (1992) give a range of 1100–2300 m.[8]
^Cheek & Jebb (2001), Clarke (1997) and Adam, Wilcock & Swaine (1992) give a lower altitudinal limit of 1500 m for N. edwardsiana.[8][24][25]
^Cheek & Jebb (2001) give a lower altitudinal limit of 1000 m for N. ephippiata.[24] The species has reportedly been collected from Bukit Raya at 2000–2270 m.[8][31]
^Adam, Wilcock & Swaine (1992) give an upper altitudinal limit of 1700 m for N. gracilis.[8]
^Adam, Wilcock & Swaine (1992) give a range of 150–1500 m for N. hirsuta,[8] while Mansur & Brearley (2008) report finding it at elevations as low as 160 m.[43]
^Cheek & Jebb (2001) give a lower altitudinal limit of 1600 m for N. lowii,[24] while Adam, Wilcock & Swaine (1992) give a range of 900–3400 m.[8]
^The lower altitudinal limit of 2000 m given for N. macrophylla in some older sources[54] is apparently incorrect.[2][55]
^Adam, Wilcock & Swaine (1992) give a lower altitudinal limit of 250 m for N. macrovulgaris.[8]
^Adam, Wilcock & Swaine (1992) give an upper altitudinal limit of 1500 m for N. rafflesiana.[8]
^The paratype of N. ramos was collected at 670 m[71] and N. kurata (which has been synonymised with N. ramos[6]) has been recorded at c. 1400 m.[33]
^Rybka, Rybková & Cantley (2005) give a range of 1200–1800 m for N. sibuyanensis,[75] while the authors of the describing paper give a range of 1500–1800 m.[76]
^Cheek & Jebb (2001) give an upper altitudinal limit of 2750 m for N. tobaica.[24]
^Cheek & Jebb (2001) give an upper altitudinal limit of 500 m for N. treubiana.[24]
^The upper altitudinal limit of 400 m is uncertain as it is based on the figure given on Google Earth for an "inexact grid-reference" associated with a herbarium specimen.[83]
^Nepenthes villosa generally grows at elevations of 2300–3240 m, but is more common at 1600–1900 m on Mount Tambuyukon.[2] Adam, Wilcock & Swaine (1992) give an upper altitudinal limit of 3400 m for this species.[8]
^ abcdefCheek, M. & M. Jebb 2013. Identification and typification of Nepenthes blancoi, with N. abalata sp. nov. from the western Visayas, Philippines. Nordic Journal of Botany31(2): 151–156. doi:10.1111/j.1756-1051.2012.00012.x
^ abcdefghijklCheek, M. & M. Jebb 2013. The Nepenthes micramphora (Nepenthaceae) group, with two new species from Mindanao, Philippines. Phytotaxa151(1): 25–34. doi:10.11646/phytotaxa.151.1.2
^ abcdefghijklmnoGronemeyer, T., W. Suarez, H. Nuytemans, M. Calaramo, A. Wistuba, F.S. Mey & V.B. Amoroso 2016. Two new Nepenthes species from the Philippines and an emended description of Nepenthes ramos. Plants5(2): 23. doi:10.3390/plants5020023
^ abcdefghijklmCheek, M. & M. Jebb 2013. Typification and redelimitation of Nepenthes alata with notes on the N. alata group, and N. negros sp. nov. from the Philippines. Nordic Journal of Botany31(5): 616–622. doi:10.1111/j.1756-1051.2012.00099.x
^ abcdeCheek, M. & M. Jebb 2013. Nepenthes alzapan (Nepenthaceae), a new species from Luzon, Philippines. Phytotaxa100(1): 57–60. doi:10.11646/phytotaxa.100.1.6
^ abcd(インドネシア語) Mansur, M. 2012. Keanekaragaman jenis tumbuhan pemakan serangga dan laju fotosintesisnya di Pulau Natuna. [Diversity on insectivorous plants and its photosynthetic rate in Natuna Island.] Berita Biologi11(1): 33–42. Abstract
^McPherson, S.R. 2010. Carnivorous Plants and their Habitats. 2 volumes. Redfern Natural History Productions, Poole.
^ abcdefLee, C.C., G. Bourke, W. Taylor, S.T. Yeo & K. Rembold 2011. Nepenthes appendiculata, a new pitcher plant from Sarawak. In: McPherson, S.R. New Nepenthes: Volume One. Redfern Natural History Productions, Poole. pp. 24–35.
^ abcdefghijklmnopqrCheek, M. & M. Jebb 2014. Expansion of the Nepenthes alata group (Nepenthaceae), Philippines, and descriptions of three new species. Blumea59: 144–154. doi:10.3767/000651914X685861
^ abcdeCheek, M., D.N. Tandang & P.B. Pelser 2015. Nepenthes barcelonae (Nepenthaceae), a new species from Luzon, Philippines. Phytotaxa222(2): 145–150. doi:10.11646/phytotaxa.222.2.7
^ abcdefgCheek, M.R. & M.H.P. Jebb 2009. Nepenthes group Montanae (Nepenthaceae) in Indo-China, with N. thai and N. bokor described as new. Kew Bulletin64(2): 319–325. doi:10.1007/s12225-009-9117-3
^ abcClarke, C.M. 1997. Nepenthes of Borneo. Natural History Publications (Borneo), Kota Kinabalu.
^ abClarke, C., C.C. Lee & V. Enar 2014. Observations of the natural history and ecology of Nepenthes campanulata. Carnivorous Plant Newsletter43(1): 7–13.
^ abcdeGronemeyer, T., F. Coritico, M. Micheler, D. Marwinski, R. Acil & V. Amoroso 2011. Nepenthes ceciliae, a new pitcher plant species from Mount Kiamo, Mindanao. In: McPherson, S.R. New Nepenthes: Volume One. Redfern Natural History Productions, Poole. pp. 412–423.
^ abcdefghijklmnopqrstuGronemeyer, T., F. Coritico, A. Wistuba, D. Marwinski, T. Gieray, M. Micheler, F.S. Mey & V. Amoroso 2014. Four new species of Nepenthes L. (Nepenthaceae) from the central mountains of Mindanao, Philippines. Plants3(2): 284–303. doi:10.3390/plants3020284
^Nooteboom, H.P. (ed.) 1987. Report of the 1982–1983 Bukit Raya Expedition. Rijksherbarium, Leiden.
^ abcdeRobinson, A.S., J. Nerz & A. Wistuba 2011. Nepenthes epiphytica, a new pitcher plant from East Kalimantan. In: McPherson, S.R. New Nepenthes: Volume One. Redfern Natural History Productions, Poole. pp. 36–51.
^ abcdefghijklmnopqrstCheek, M. & M. Jebb 2013. Recircumscription of the Nepenthes alata group (Caryophyllales: Nepenthaceae), in the Philippines, with four new species. European Journal of Taxonomy69: 1–23. doi:10.5852/ejt.2013.69
^ abcdefPhillipps, A., A. Lamb & C.C. Lee 2008. Pitcher Plants of Borneo. Second Edition. Natural History Publications (Borneo), Kota Kinabalu.
^ abcdeMcPherson, S., J. Cervancia, C. Lee, M. Jaunzems, A. Fleischmann, F. Mey, E. Gironella & A. Robinson 2010. Nepenthes gantungensis (Nepenthaceae), a new pitcher plant species from Mount Gantung, Palawan, Philippines. In: S.R. McPherson Carnivorous Plants and their Habitats. Volume 2. Redfern Natural History Productions, Poole. pp. 1286–1295.
^ abcdefGronemeyer, T., A. Wistuba, V. Heinrich, S. McPherson, F. Mey & A. Amoroso 2010. Nepenthes hamiguitanensis (Nepenthaceae), a new pitcher plant species from Mindanao Island, Philippines. In: S.R. McPherson Carnivorous Plants and their Habitats. Volume 2. Redfern Natural History Productions, Poole. pp. 1296–1305.
^ abcdScharmann, M. & T.U. Grafe 2013. Reinstatement of Nepenthes hemsleyana (Nepenthaceae), an endemic pitcher plant from Borneo, with a discussion of associated Nepenthes taxa. Blumea58(1): 8–12. doi:10.3767/000651913X668465
^Clarke, C., J.A. Moran & C.C. Lee 2011. Nepenthes baramensis (Nepenthaceae) – a new species from north-western Borneo . Blumea56(3): 229–233. doi:10.3767/000651911X607121
^ abcdefRobinson, A., J. Nerz, A. Wistuba, M. Mansur & S. McPherson 2011. Nepenthes lamii Jebb & Cheek, an emended description resulting from the separation of a two-species complex, and the introduction of Nepenthes monticola, a new species of highland pitcher plant from New Guinea. In: McPherson, S.R. New Nepenthes: Volume One. Redfern Natural History Productions, Poole. pp. 522–555.
^ abcdeMcPherson, S., G. Bourke, J. Cervancia, M. Jaunzems, E. Gironella, A. Robinson & A. Fleischmann 2011. Nepenthes leonardoi (Nepenthaceae), a new pitcher plant species from Palawan, Philippines. Carniflora Australis8(1): 4–19.
^Bourke, G. 2007. Exploring the upper reaches of Gunung Trus Madi. Carniflora Australis (9): 9–16.
^ abcdefCheek, M. & M. Jebb 2016. A new section in Nepenthes (Nepenthaceae) and a new species from Sulawesi. Blumea61: 59–62. doi:10.3767/000651916X691510
^ abcdefCheek, M. & M.H.P. Jebb (2016). Nepenthes minima (Nepenthaceae), a new pyrophytic grassland species from Sulawesi, Indonesia. Blumea61: 181–185. doi:10.3767/000651916X693509
^ abcdefMansell, G. & W. Suarez (2016). Nepenthes nebularum, a new species from Mindanao, Philippines. Carnivorous Plant Newsletter45(4): 132–139.
^ abcdeNerz, J., A. Wistuba, C.C. Lee, G. Bourke, U. Zimmermann & S. McPherson 2011. Nepenthes nigra, a new pitcher plant from Central Sulawesi. In: McPherson, S.R. New Nepenthes: Volume One. Redfern Natural History Productions, Poole. pp. 468–491.
^ abcdeMcPherson, S., J. Cervancia, C. Lee, M. Jaunzems, A. Fleischmann, F. Mey, E. Gironella & A. Robinson 2010. Nepenthes palawanensis (Nepenthaceae), a new pitcher plant species from Sultan Peak, Palawan Island, Philippines. In: S.R. McPherson Carnivorous Plants and their Habitats. Volume 2. Redfern Natural History Productions, Poole. pp. 1332–1339.
^ abcWilson, G.W. & S. Venter (2016). Nepenthes parvula (Nepenthaceae), a new species from Cape York, Queensland, Australia. Phytotaxa277(2): 199–204. doi:10.11646/phytotaxa.277.2.7
^McPherson, S.R. 2011. Observations of Nepenthes philippinensis and related taxa. In: New Nepenthes: Volume One. Redfern Natural History Productions, Poole. pp. 382–395.
^ abLee, C.C., S. McPherson, G. Bourke & M. Mansur 2009. Nepenthes pitopangii (Nepenthaceae), a new species from central Sulawesi, Indonesia. The Gardens' Bulletin Singapore61(1): 95–100.
^ abcdeGronemeyer, T., S. McPherson, F. Coritico, M. Micheler, D. Marwinski & V. Amoroso 2011. Nepenthes pulchra, a new pitcher plant species from Mount Kiamo, Mindanao. In: McPherson, S.R. New Nepenthes: Volume One. Redfern Natural History Productions, Poole. pp. 424–439.
^ abcdefCheek, M. & M. Jebb 2013. Nepenthes ramos (Nepenthaceae), a new species from Mindanao, Philippines. Willdenowia43(1): 107–111. doi:10.3372/wi.43.43112
^ abcdeCheek, M. 2011. Nepenthes robcantleyi sp. nov. (Nepenthaceae) from Mindanao, Philippines. Nordic Journal of Botany29(6): 677–681. doi:10.1111/j.1756-1051.2011.01449.x
^ abcdefCheek, M. & M. Jebb 2013. Nepenthes samar (Nepenthaceae), a new species from Samar, Philippines. Blumea58(1): 82–84. doi:10.3767/000651913X673513
^Mey, F.S., L.H. Truong, D.V. Dai & A.S. Robinson 2011. Nepenthes thorelii, an emended description and novel ecological data resulting from its rediscovery in Tay Ninh, Vietnam. In: McPherson, S.R. New Nepenthes: Volume One. Redfern Natural History Productions, Poole. pp. 104–131.
^ abcdefgCheek, M. & M. Jebb 2013. Nepenthes ultra (Nepenthaceae), a new species from Luzon, Philippines. Blumea, published online on October 24, 2013. doi:10.3767/000651913X675124
^ abcdefLee, C.C., A. Wistuba, J. Nerz, U. Zimmermann, A.P. Paserang & R. Pitopang 2011. Nepenthes undulatifolia, a new pitcher plant from South East Sulawesi. In: McPherson, S.R. New Nepenthes: Volume One. Redfern Natural History Productions, Poole. pp. 492–505.
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^ abcMcPherson, S.R. 2011. The discovery of Nepenthes sp. 'Anipahan'. In: New Nepenthes: Volume One. Redfern Natural History Productions, Poole. pp. 330–345.
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^Meimberg, H., A. Wistuba, P. Dittrich & G. Heubl 2001. Molecular phylogeny of Nepenthaceae based on cladistic analysis of plastid trnK intron sequence data. Plant Biology (Stuttgart)3(2): 164–175. doi:10.1055/s-2001-12897