Nepenthes albomarginata

Appearance

''Nepenthes albomarginata'' is a climbing plant. The stem may reach lengths of up to 4 metres and is up to 5 millimetres in diameter. Internodes are cylindrical in cross section and up to 15 centimetres long.



Leaves are coriaceous in texture. The lamina or leaf blade is lanceolate in shape and up to 25 centimetres long by 2 centimetres wide. It has an acute apex and its base is gradually attenuate and amplexicaul. The leaves of this species are characteristic in that they completely lack a petiole. Longitudinal veins are indistinct. Tendrils are up to 20 centimetres long.

Rosette and lower pitchers are bulbous in the basal third and cylindrical above. They are relatively small, reaching only 15 centimetres in height by 4 centimetres in width. A pair of fringed wings up to 5 millimetres wide runs down the front of each pitcher. The pitcher mouth is round and rises to form a short neck at the rear. The peristome is cylindrical in cross section, up to 2 millimetres wide, and bears indistinct teeth. The inner portion of the peristome accounts for around 34% of its total cross-sectional surface length. A dense band of short white trichomes is present directly below the peristome, although these may be missing from pitchers that have caught termites. The glandular region covers the bulbous portion of the pitcher's inner surface. The lid or operculum is suborbicular and lacks appendages. An unbranched spur long) is inserted near the base of the lid.

Upper pitchers are similar to their lower counterparts in most respects. They are cylindrical-infundibular throughout and have a pair of ribs in place of wings.

''Nepenthes albomarginata'' has a racemose inflorescence that is usually longer in male plants. The peduncle is up to 25 centimetres long, while the rachis reaches lengths of up to 40 centimetres . Partial peduncles are one- or two-flowered, up to 30 millimetres long, and lack a bract. Sepals are obovate to oblong in shape and up to 4 millimetres long. A study of 120 pollen samples taken from a herbarium specimen ) found the mean pollen diameter to be 31.8 μm .

Most parts of the plant are covered in a dense indumentum of very short, stellate white hairs. However, the underside of the lamina bears a dense covering of long hairs.

Naming

In 2001, Clarke performed a cladistic analysis of the ''Nepenthes'' species of Sumatra and Peninsular Malaysia using 70 morphological characteristics of each taxon. The following is a portion of the resultant cladogram, showing "Clade 6", which is only weakly supported at 50%. The sister pair of ''N. angasanensis'' and ''N. mikei'' has 79% support.



...snipped...

Habitat

''Nepenthes albomarginata'' is a widespread species, occurring in Borneo, Peninsular Malaysia, and Sumatra. It is also found on smaller islands such as Nias and Penang. It has an altitudinal distribution of 0–1200 m above sea level.


Its typical habitat consists of ''kerangas'' forest, but it has also been recorded from the summit vegetation of lowland peaks. It is known from peat and limestone substrates.

Evolution

''Nepenthes albomarginata'' was first collected by Thomas Lobb in 1848. It was formally described a year later by John Lindley in ''The Gardeners' Chronicle''.

The species was introduced into cultivation in the United Kingdom in 1856.


In the 1996 book ''Pitcher-Plants of Borneo'', ''N. albomarginata'' is given the vernacular name white-collared pitcher-plant. This name, along with all others, was dropped from the much-expanded second edition, published in 2008.