Nepenthes neoguineensis /nɪˈpɛnθiːz ˌniːoʊɡɪniˈɛnsɪs/ is a tropical pitcher plant native to the island of New Guinea, after which it is named.

[5] Nepenthes neoguineensis was described by John Muirhead Macfarlane in 1911 based on the specimen Versteeg 1746, which consists of female plant material.

[3] However, in his seminal monograph "The Nepenthaceae of the Netherlands Indies", B. H. Danser showed that it belonged to a closely related but distinct species, which he named N.

The stem is up to 6 mm thick and cylindrical to obtusely angular in cross section, especially in the upper part of the internodes.

Pinnate veins ascend obliquely from the midrib and are irregularly reticulate in the outer part of the lamina.

[4] Upper pitchers gradually arise from the ends of the tendrils, forming a 7 to 23 mm wide curve.

A pair of fringed wings (≤8 mm wide) runs down the entire length of the pitcher.

Round, depressed glands are present on the undersurface of the lid, being concentrated and increasing in size towards the middle.

Tendrils are densely hirsute when young, becoming only hairy near the pitcher or entirely glabrous when mature.

Upper pitchers are generally yellowish-green, often with a darker peristome and bright red lid.

[4] Nepenthes neoguineensis is native to New Guinea and the nearby D'Entrecasteaux Islands, and may also occur on Misool (see N. sp.

Danser considered N. tomoriana from Sulawesi and N. distillatoria from Sri Lanka to be the closest relatives of N. neoguineensis.

The wings are less developed in the upper pitchers of N. papuana and the fringe elements are more closely spaced.

[4] Based on the structure of its inflorescence, it has been suggested that N. neoguineensis belongs to a group of relatively primitive Nepenthes species, which includes N. distillatoria and N.

Folia mediocria petiolata, lamina lanceolata, nervis longitudinalibus utrinque 3-4, vagina caulis 1/2 amplectente ; ascidia rosularum et inferiora ignota ; ascidia superiora mediocria, subcylindrica, sub medio et os versus paulum ampliata, alis 2 fimbriatis ; peristomio operculum versus acuminato, cylindrico v. applanato, 1-1 1/2 cm lato, costis 1/3-1/4 mm distantibus, dentibus fere 0 ; operculo suborbiculari, facie inferiore plano ; inflorescentia panicula v. racemus pedicellis inferioribus ad 35 mm longis 3-floris superioribus brevioribus, 2- v. 1-floris ; indumentum parcum villosum, in caulibus foliisque fere 0, in ascidiis iuventute densum, denique parcum, in inflorescentiis et floribus densum permanens.