Nepenthes Lamii - Description

Description

Nepenthes lamii reaches a maximum height of around 4 m, although plants growing towards the upper altitudinal limit of this species are greatly stunted shrublets. The stem, which may be branched, is rounded or angular in cross section and has internodes up to 8 cm long.

A rosette plant with lower pitchers growing near Tembagapura at 2600 m (left) and a single lower pitcher at 2800 m (right)

Leaves are thinly coriaceous and sessile. The lamina (leaf blade) is most commonly linear, but may also be lanceolate. It reaches 22 cm in length by 5 cm in width. It has an acute to acuminate apex and an obtuse base that may be decurrent for more than 2 cm down the stem, although it is variable in this respect. Three to four longitudinal veins are typically present on either side of the midrib, restricted to the distal quarter to third of the lamina, although they may number as many as 5 or as few as 0. Pinnate veins, which may or may not be distinct, emerge obliquely from the midrib to form an irregular network in the distal half of the lamina. Tendrils may be densely glandular in some specimens. Laminae are typically green throughout, but may be tinged with purple, especially in stunted plants from higher elevations. The midrib and tendrils are often yellow and turn orange to red upon exposure to strong sunlight.

Rosette and lower pitchers are typically ovate in the basal half of the pitcher cup, becoming cylindrical and sometimes slightly infundibular above. A conspicuous hip often delimits these two parts of the trap. Terrestrial pitchers may also be entirely ovate. They are relatively small, rarely exceeding 7 cm in height by 3 cm in width, although they occasionally reach 12 cm by 4 cm. A pair of wings (≤8 mm wide) runs down the ventral surface of the pitcher cup. The wings bear fringe elements up to 5 mm long. The pitcher mouth is suborbicular and has an oblique insertion. The peristome is cylindrical and becomes flattened and broader towards the sides and rear, measuring up to 7 mm in width. It bears ribs up to 0.5 mm high and spaced up to 0.8 mm apart. On the inner margin of the peristome, the ribs terminate in teeth up 1 mm long. The pitcher lid or operculum is orbicular to elliptic with a rounded apex and a rounded to cordate base. It bears no appendages, although the midline may be thickened into a 1 mm high ridge. It reaches 4.5 cm in length by 3.8 cm in width. The lower surface of the lid bears numerous nectar glands. Most are orbicular and measure 0.1–0.2 mm in diameter; this type occurs at a density of 1500–2000/cm2. Larger, longitudinally elliptic glands of 0.4 mm, and occasionally even up to 3 mm, are concentrated around the midline. An unbranched spur measuring up to 5 mm in length is inserted near the base of the lid. It may or may not be flattened. Lower pitchers are typically reddish on their outer surface, often having speckles of a darker red colour. The inner surface varies from white to light orange. The peristome may be orange, through red, to purple. The lid is often yellowish on its lower surface and the same colour as the pitcher cup on its upper surface. Stunted plants from higher altitudes typically produce dark terrestrial pitchers.

An upper pitcher (left) and a climbing plant with aerial traps (right), both found near Tembagapura at 2800 m

Upper pitchers are infundibular and somewhat inflated in the basal quarter to third of the pitcher cup, becoming cylindrical or slightly infundibular above. A conspicuous hip often delimits these two parts of the trap. Rarely they may be wholly obovoid. Aerial traps are considerably larger than their terrestrial counterparts, growing to 18 cm in height by 5 cm in width. Ribs are present in place of wings. The peristome is cylindrical and up to 5 mm wide, being either uniformly broad throughout or slightly expanded at the sides and rear. Other parts are similar to those found in terrestrial traps. Aerial pitchers are usually yellowish throughout, occasionally with tinges of orange or red in older specimens. The ventral ridges are sometimes completely red. The inner surface may be white to cream coloured. The peristome ranges in colour from yellow to red, whereas the lid is most commonly yellow throughout.

Nepenthes lamii has a racemose inflorescence up to 14 cm long. The peduncle constitutes up to 7 cm of this length and has a basal width of around 2 mm. Flowers are borne solitarily on pedicels (≤10 mm long) that lack bracts. Tepals are elliptic and measure up to 3 mm in length by 3.3 mm in width. The androphore is up to 2.5 mm long and bears an anther head measuring up to 1.25 mm by 1.5 mm.

Most parts of the plant lack a persistent indumentum, being glabrous. A very sparse covering of pale brown, woolly-scurfy hairs measuring 0.2–0.4 mm is present on developing parts. The only mature parts that retain an indumentum are the inflorescence and tendrils, which bear an inconspicuously puberulent covering of simple, black hairs of around 0.3 mm.