maxima. Related species Danser considered N. tomoriana from Sulawesi and N. distillatoria from Sri Lanka to be the closest relatives of N. neoguineensis. He also noted its similarity to N. papuana, stating: "N. papuana is so much alike N. neoguineensis in its vegetative parts, that only the complete knowledge of the generative parts has suggested me to establish a new species". The two taxa can be distinguished on the basis of several morphological features. N. papuana has a racemose inflorescence, while that of N. neoguineensis is a panicle or panicle-like raceme. Furthermore, the inflorescence of N. papuana usually bears only one-flowered pedicels, both in male and female plants. Those of N. neoguineensis can be up to four-flowered. The lamina of N. papuana has very distinct longitudinal veins and indistinct pinnate veins, whereas in N. neoguineensis the opposite is true. In addition, the leaves of N. papuana are very densely ciliate, much more so than in N. neoguineensis. The wings are less developed in the upper pitchers of N. papuana and the fringe elements are more closely spaced. 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. pervillei. Natural hybrids Where their ranges overlap, N. neoguineensis is known to hybridise with N. ampullaria and N. maxima. The hybrid plants are generally intermediate in appearance between their parent species. Notes a.Zippel 177 was collected in 1828 near Triton Bay. Zipelius explored this area between June and August and probably collected it during this time. The habitat is recorded as "ad parietines humid, in convallibus montium". The specimen is deposited at Herbarium Lugduno-Batavum in Leiden. It does not include flowers or fruits. b.Versteeg 1268 was collected on June 19, 1907, on the "first Nepenthes-hill near Sabang (in West Papua near the Unir River) at an elevation of 30 m. It is deposited at the Bogor Botanical Gardens (formerly the Herbarium of the Buitenzorg Botanic Gardens) in Java. It does not include flowers or fruits. c.Versteeg 1746 was collected on September 25, 1907, on a "Nepenthes-hill". It is deposited at the Bogor Botanical Gardens and consists of female plant material. d.Gjellerup 122 was collected on May 10, 1910, in Hollandia at an elevation of 30 m. It is preserved in alcohol and deposited at the Bogor Botanical Gardens. It consists of male plant material.