Nepenthes diatas is a tropical pitcher plant endemic to northern Sumatra, Indonesia, formally described in 1997 by Matthew Jebb and Martin Cheek. The species name diatas comes from the Indonesian word for “above” or “on top,” referencing both its high-altitude habitat and its location in the northernmost region of Sumatra. It is part of the N. singalana group and is known for its robust growth and distinctive pitcher morphology.
 
Habitat Overview: Climate and Soil
N. diatas grows in montane scrub and mossy forest environments at elevations between 2,000 and 2,900 meters above sea level. These habitats are cool, humid, and cloud-covered, with frequent rainfall and nutrient-poor soils. The species thrives in acidic, organic-rich substrates, often on steep slopes and summit ridges. Its carnivorous pitchers allow it to trap insects and supplement nutrients in these challenging conditions.
 
Natural Range and Distribution
This species is endemic to Aceh Province in northern Sumatra, specifically found at the summit area of Gunung Bandahara. Its distribution is limited to high-altitude zones, and while it is not currently considered critically endangered, its narrow range makes it vulnerable to habitat disturbance. It is listed as Least Concern by the IUCN.
 
Physical Characteristics
Nepenthes diatas is a terrestrial subscandent shrub, growing up to 2.5 meters tall. The stem is quadrangular, with internodes 1–3.5 cm long. Leaves are thinly coriaceous, sessile, and oblanceolate, measuring 9.5–17 cm long and 2.5–3.5 cm wide, with bases that clasp the stem and may be auriculate.
The upper pitchers are:
Ventricose in the lower third, cylindrical to slightly funnel-shaped above
14–22 cm tall, with prominent ridges and occasionally short fringed wings
Peristome is woody, 5–15 mm wide, with ribs and teeth up to 2.5 mm long
Lid is orbicular, 3.2–6.5 cm in diameter, with numerous nectar glands but no appendage
Inflorescence is up to 38 cm long, with clustered flowers in the upper portion
The plant is covered in reddish-brown hairs, especially on tendrils and inflorescences, and pitchers are typically reddish-brown.
 
Similar Species and Differentiation
Nepenthes diatas is part of the N. singalana group, and closely resembles:
N. singalana: differs by having a woody peristome (vs. papery in N. singalana)
N. spathulata: similar pitcher shape but again differs in peristome texture
N. densiflora: shares some morphological traits but differs in pitcher proportions and lid structure.
 
These distinctions are important for accurate identification, especially in regions where multiple Nepenthes species coexist.