Which species of Nepenthes is found at the highest altitude?

Nepenthes lamii is the Nepenthes species found at the highest known altitude.

This New Guinea pitcher plant has been recorded from about 1,460 to 3,520 metres above sea level. Its upper limit on Doorman Top in West Papua is higher than that recorded for any other recognised Nepenthes species. An unidentified Nepenthes from Papua has been reported at a similar elevation, but the named species record belongs to N. lamii.

The species is endemic to high peaks in central Papua, including Doorman Top and Mount Erica in the Hellwig Mountains. At lower elevations it can grow as a scrambling climber or epiphyte; near the summit it becomes more compact and grows among moss, scrub, and grass above the tree line.

Nepenthes villosa is a frequent distractor because it is the highest-growing Nepenthes in Borneo, reaching roughly 3,240 metres. N. lamii surpasses it because the comparison is worldwide, not limited to Borneo.