Nepenthes Papuana - Description

Description

Nepenthes papuana is a climbing plant. The stem is cylindrical in cross section and 5 to 7 mm thick. Internodes are 2 to 5 cm long. Older plants produce short shoots and rosettes near the base of the stem.

Leaves are sessile or shortly petiolate and coriaceous in texture. The lamina is lanceolate and reaches 30 cm in length and 5 cm in width. It has an acute apex and is attenuate towards the base. Usually around 4 to 6 longitudinal veins are present on either side of the midrib. Pinnate veins are indistinct. Tendrils are about as long as the lamina and 1 to 2 mm thick.

Rosette and lower pitchers are obliquely ovate in the lower part and gradually narrowed above, reaching 7 cm in height and 2.5 cm in width. A pair of fringed wings (≤4 mm wide) run down the front of the pitcher. The pitcher mouth is oblique and slightly incurved towards the lid. The peristome is 1 to 2 mm wide and bears small teeth. The inner surface of the pitcher is glandular in the lower two-fifths to one-third. The lid or operculum is suborbicular, slightly cordate, and 1 to 2 cm long and wide. The lower surface of the lid bears no appendages and has many small glands concentrated near the centre. An unbranched spur is inserted at the base of the lid.

Upper pitchers gradually arise from the ends of the tendrils, forming a 6 to 12 mm wide curve. They are shortly infundibular in the lower part, slightly ventricose for around a third of their height, and wholly tubulose in the upper part. Aerial pitchers may be up to 15 cm high and 3 cm wide. Two narrow wings (≤2.5 mm wide) are present over the entire length of the pitcher. They may or may not have fringe elements. The mouth is oblique and acute towards the lid. The flattened peristome is up to 2 mm wide and bears small teeth that are up to twice as long as they are wide. The inner surface of the pitcher is glandular in the ventricose part. The glands occur at a density of 400 to 500 per square centimetre. The lid is nearly round, being only slightly longer than it is wide. It may be up to 3.5 cm long and 3.25 cm wide. Small, depressed glands are present on the undersurface of the lid, being concentrated near the basal part of the midrib. The spur is flattened, 2 to 3 mm long, and unbranched.

Nepenthes papuana has a racemose inflorescence. In male plants, the peduncle is about 6 cm long and 2 mm wide, while in female plants it is 12 cm long and 2.5 mm thick. The rachis is up to 15 cm long. Pedicels are up to 15 mm long and do not have a bracteole. They are almost always one-flowered, although lower ones may be two-flowered. Tepals are suborbicular in male plants and oblong in female plants. Stamens are 3 to 4 mm long including the anthers. The ovary is sessile. Fruits are 25 to 35 mm long and bear lanceolate valves. The filiform seeds are 12 to 15 mm long.

The indumentum of N. papuana is generally sparse and short. The stem and lamina are mostly glabrous, except for the midrib, which has caducous brown hairs on its lower surface, and the leaf margin, which bears persistent brown-velvety hairs. Tendrils are similarly hairy to the underside of the midrib. Pitchers have a dense indumentum of short, stellate hairs when young. A sparse covering of these hairs is persistent in lower pitchers, whereas in upper pitchers they are mostly caducous. Developing inflorescences are densely tomentose, becoming more sparsely tomentose when mature.

Lower pitchers are generally reddish throughout with red blotches on their inner surface. Upper pitchers are usually green throughout but may also be reddish. Herbarium specimens are red-brownish, with the upper surface of the leaves being yellow-brownish.