Over het geslacht Nepenthes

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"Over het geslacht Nepenthes" (lit. "Concerning the genus Nepenthes") is a Dutch-language monograph by Pieter Willem Korthals on the tropical pitcher plants of the genus Nepenthes.{{in lang|nl}} Korthals, P.W. 1839. Over het geslacht Nepenthes. In: C.J. Temminck 1839–1842. Verhandelingen over de Natuurlijke Geschiedenis der Nederlandsche overzeesche bezittingen; Kruidkunde. Leiden. pp. 1–44, t. 1–4, 13–15, 20–22. It was published in 1839 in Coenraad Jacob Temminck's Verhandelingen over de Natuurlijke Geschiedenis der Nederlandsche overzeesche bezittingen. It is generally regarded as the first monograph on Nepenthes.Clarke, C.M. 1997. Nepenthes of Borneo. Natural History Publications (Borneo), Kota Kinabalu.Phillipps, A., A. Lamb & C.C. Lee 2008. Pitcher Plants of Borneo. Second Edition. Natural History Publications (Borneo), Kota Kinabalu.

Korthals recognised 9 species: N. ampullaria, N. bongso, N. boschiana, N. distillatoria, N. gracilis, N. gymnamphora, N. madagascariensis, N. phyllamphora (now known as N. mirabilis),McPherson, S.R. 2009. Pitcher Plants of the Old World. 2 volumes. Redfern Natural History Productions, Poole. and N. rafflesiana. Three of these—N. bongso, N. boschiana, and N. gracilis—were described for the first time, and six were illustrated with hand-coloured lithographs.

{{multiple image

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| footer = The six hand-coloured lithographs from Korthals's monograph (left to right): N. ampullaria, N. bongso, N. boschiana, N. gracilis, N. gymnamphora, and N. phyllamphora (N. mirabilis)

| image1 = Nepenthes ampullaria Korthals 1839.JPG

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| image2 = Nepenthes bongso Korthals 1839.JPG

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| image3 = Nepenthes boschiana Korthals 1839.JPG

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| image4 = Nepenthes gracilis Korthals 1839.JPG

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| image5 = Nepenthes gymnamphora Korthals 1839.JPG

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| image6 = Nepenthes mirabilis Korthals 1839.JPG

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