Nepenthes Benstonei - Description

Description

Nepenthes benstonei is a climbing plant. The stem, which may be branched, can attain a length of 10 m and is up to 0.6 cm in diameter. Internodes are cylindrical and up to 15 cm long.

Leaves are coriaceous and sessile to sub-petiolate. The lamina is usually broadly linear-lanceolate in shape, but may also be slightly spathulate. Its base is a broad, amplexicaul sheath with decurrent margins. The lamina can reach 60 cm in length and 9 cm in width. It has a rounded to acute apex. The margins of the lamina usually meet the tendril unequally on both sides, being up to 3 mm apart. Three to five longitudinal veins are present on either side of the midrib. Pinnate veins are almost indistinct. Tendrils are up to 60 cm long.

Lower pitchers of two different forms of N. benstonei, showing the colour variation exhibited by this species

Rosette and lower pitchers reach 20 cm in height and 5 cm in width. They are ovoid in the lower part and cylindrical above, with a pronounced hip in the middle. A pair of fringed wings (≤4 mm wide) runs the whole length of the pitcher cup. The pitcher mouth is round to ovate and oblique throughout. The peristome is up to 6 mm wide and bears very small but distinct teeth along its inner margin. The pitcher lid is ovate and lacks appendages. It bears a short but distinct keel and often has a very broad insertion. A simple or bifurcate spur (≤12 mm long) is inserted near the base of the lid.

Upper pitchers are similar in most respects to their lower counterparts. They are up to 20 cm high and 3 cm wide. They are infundibular in the lowermost part, narrowly ovoid in the next part, and cylindrical above. The peristome lacks teeth in upper pitchers. The lid is narrower and has a less obtuse apex. The spur is simple and much smaller, reaching only 5 mm in length.

An intermediate pitcher (left) and an upper pitcher with an old infructescence (right)

Nepenthes benstonei has a racemose inflorescence. The peduncle is up to 20 cm long and the rachis up to 30 cm long. The first flower is generally borne on a pedicel, sometimes with a simple, lanceolate bracteole (≤1.5 cm long). Subsequent flowers are produced on pedicels or two-flowered partial peduncles, which lack bracteoles. Sepals are ovate and around 4 mm long. Male inflorescences usually bear around twice as many flowers as female ones. N. benstonei is one of the few Nepenthes species known to produce multiple inflorescences concurrently on a single stem. Two to three are usually produced, originating from sequential nodes at the top of the stem. This unusual reproductive habit has also been observed, although much more rarely, in N. alba, N. ampullaria, N. attenboroughii, N. rigidifolia, N. sanguinea, and N. thai. It is seen even more frequently in N. philippinensis.

The stem and lamina have a sparse indumentum of simple white hairs. Short, branched reddish-brown hairs line the margins of the lamina. The outer surfaces of the pitchers bear a sparse covering of short, branched red hairs. The same hairs are more densely present on the margins of the lid and upper part of the pitcher directly below the peristome. Immature inflorescences have an indumentum of short white and red hairs throughout.

The stem and leaves of N. benstonei bear a thick, waxy cuticle that often gives a whitish-blue sheen to the lamina and pitchers. Inflorescences are distinctly waxy throughout.

No infraspecific taxa of N. benstonei have been described.