Which Nepenthes species is commonly called the fanged pitcher-plant?

The Nepenthes species commonly called the fanged pitcher-plant is Nepenthes bicalcarata.

The name refers to the pair of prominent, sharp spines beneath the lid of its pitcher. The species name bicalcarata comes from Latin for “two-spurred.” Nepenthes bicalcarata is endemic to Borneo and is one of the largest species in its genus, with climbing stems reported to reach about 20 metres.

Its pitchers can exceed one litre in volume, while the two lid-area spines may grow to roughly 3 centimetres long. Botanists have proposed that the spines help position or attract insects above the pitcher opening, where a wet, slippery peristome can make prey lose its footing.

This species is also notable for its relationship with the ant Camponotus schmitzi. The ants live in hollow tendrils and feed around the pitchers, while the plant gains benefits from the association. Do not confuse the common name with a genus-level label: “fanged pitcher-plant” specifically identifies N. bicalcarata, not every Nepenthes with toothed or spiny structures.