Nepenthes ampullaria (/nɪˈpɛnθiːz ˌæmpʊˈlɛəriə/; Latin ampulla meaning "flask") is a very distinctive and widespread species of tropical pitcher plant, present in Borneo, the Maluku Islands, New Guinea, Peninsular Malaysia, Singapore, Sumatra, and Thailand.

[2][3][4][5][6] Nepenthes ampullaria, unlike other members of its genus, has evolved away from carnivory and the plants are partly detritivores, collecting and digesting falling leaf litter in their pitchers.

[11] Due to its unique pitcher morphology and unusual growth habit, it is difficult to confuse N. ampullaria with any other species in the genus.

Francis Ernest Lloyd translated Troll's 1932 account of this species as follows:[12] "I came across N. ampullaria among the massive vegetations of a swamp-forest on the island of Siberut off the west coast of Sumatra.

[13] One of the most widespread Nepenthes species, N. ampullaria is native to Borneo, the Maluku Islands, New Guinea, Peninsular Malaysia, Singapore, Sumatra, and Thailand.

[18] Nepenthes ampullaria has largely moved away from carnivory and acquires a substantial portion of its nutrients from digesting leaf matter that falls to the forest floor.

The species has developed several unique traits as a consequence of its adaptation to trapping leaf litter:[15] It has been shown that foliar stable nitrogen isotope (15N) abundance in N. ampullaria plants growing under forest canopy (litterfall present) is significantly lower than in plants without access to litterfall.

A 2003 study estimated that N. ampullaria plants growing under forest canopy derive 35.7% (±0.1%) of their foliar nitrogen from leaf litter.