Nepenthes Izumiae - Description

Description

Nepenthes izumiae is a climbing plant growing to a height of 8 m. The stem ranges in colour from green to reddish.

A young plant with lower pitchers (left) and a closeup of a lower/intermediate pitcher (right)

The lamina (leaf blade) varies in shape and may be linear, lanceolate, or spathulate. It measures up to 28 cm in length by 8 cm in width and may have a frilled margin. The lamina has an acute apex and narrows towards the base, widening again just before the point of attachment. Longitudinal veins are inconspicuous. Tendrils are up to 30 cm long and often have a sub-apical or even peltate insertion, joining the lamina on the underside, before the apex. The lamina is green throughout, whereas the midrib and tendril may be green to reddish.

Rosette and lower pitchers are typically ovate in the basal quarter to 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 be quite large, reaching 30 cm in height by 6 cm in width. A pair of fringed wings (≤6 mm wide) runs down the ventral surface of the trap, bearing filaments up to 12 mm long. The peristome is cylindrical at the front and becomes flattened and broader towards the sides and rear, measuring up to 3 cm in width. It bears ribs up to 2 mm high and spaced up to 2.5 mm apart. These ribs terminate in teeth (≤8 mm long) on the inner margin of the peristome, the largest being located towards the top. There is often a gap of several millimetres separating the two lobes of the peristome directly below the lid. The pitcher lid or operculum is ovate to orbicular and typically has a cordate base as well as a frilled margin. It measures up to 6 cm in length by 4.5 cm in width. A triangular or hook-shaped basal crest (≤1 cm long) is commonly present on the lower surface of the lid. An unbranched spur measuring up to 10 mm in length is inserted near the base of the lid. Lower pitchers typically have a very dark pigmentation, being purplish-black throughout. However, the indumentum covering the traps can give them an orange or brownish sheen. The peristome is generally purple, black, or dark brown, but may have lighter coloured teeth ranging from green, through yellow, to white. The inner surface of the pitcher may be light yellow, white, or light purple, and often bears purple speckles. The pitcher lid is often yellow or green on the underside and dark purple on its upper surface. Occasionally, the pitcher may be yellowish-green throughout with a black peristome.

Left: A lower pitcher exhibiting unusually reddish colouration
Centre: A closeup of the hook-shaped basal crest that is often present in this species
Right: Details of the well developed peristome, with the largest teeth splayed forward at the top

Upper pitchers are narrowly infundibular in the basal third to half of the pitcher cup and cylindrical above. A constriction and associated hip often delimit these two parts. Aerial traps are smaller than their terrerstrial counterparts, reaching 20 cm in height by 4 cm in width. In upper pitchers, the wings are reduced to ribs. The peristome, which reaches up to 8 mm in width, is cylindrical and expanded at the sides and rear. It bears ribs up to 0.5 mm high and spaced up to 0.5 mm apart as well as teeth up to 1.5 mm long. The pitcher lid is sub-orbicular to slightly ovate and has a cordate base. It measures up to 4.5 cm in length by 4 cm in width. It may or may not bear an appendage on its underside. The spur is simple or branched and attains a length of 5 mm. Upper pitchers exhibit a similar pigmentation to lower pitchers, but are typically lighter.

Nepenthes izumiae has a racemose inflorescence up to 18 cm long, of which the peduncle constitutes up to 10 cm and the rachis up to 8 cm. Flowers are borne solitarily on pedicels (≤5 mm long) that lack bracts. Tepals are ovate and up to 6 mm long. Fruits reach 15 mm in length. The structure of the male inflorescence has not been documented.

An indumentum of red, brown or white hairs up to 1 mm long may be present on the laminar margins, pitchers (particularly lower ones), tendrils, and parts of the inflorescence.