Nepenthes dubia

Description

Nepenthes dubia is a tropical pitcher plant endemic to Sumatra, where it grows at an altitude of 1600–2700 m above sea level. The specific epithet dubia is the Latin word for "doubtful". Leaves are sessile and coriaceous. The lamina is lanceolate-spathulate in form. It may be up to 10 cm long and 2 cm wide. It has an acute apex and is gradually attenuate towards the base, which clasps the stem for one third to a half of its circumference. Around three pairs of longitudinal veins are present on the lamina, originating from the basal third of the midrib. Pinnate veins are oblique and irregularly reticulate, although they are not easily distinguishable. Tendrils can be up to 15 cm long and may or may not have a curl. Rosette and lower pitchers are rarely produced. They are narrowly infundibular in the lower two-thirds, becoming ovoid above, and are sharply contracted below the rim. Terrestrial pitchers are relatively small, reaching 5 cm in height and 3.5 cm in width. A pair of fringed wings (≤3 mm wide) runs down the upper third of the pitcher beneath the rim. The glandular region covers the lower two-thirds of the inner surface. The pitcher mouth is round and slightly raised at the back. The peristome is cylindrical, up to 3 mm wide, and bears indistinct teeth. The lid or operculum is ovate and slightly raised in the middle. It bears no appendages. An unbranched spur (≤4 mm long) is inserted at the base of the lid.