Tropical pitcher plant (Nepenthes hamiguitanensis)

Description

Nepenthes hamiguitanensis is a tropical pitcher plant endemic to a single peak on the Philippine island of Mindanao, where it grows at elevations of 1200–1600 m above sea level. Once thought to be a natural hybrid between N. micramphora and N. peltata, this plant is now considered a species of possible hybridogenic origin. It produces squat upper pitchers that vary greatly in pigmentation, from red speckled to yellow throughout. The specific epithet hamiguitanensis is derived from the name of Mount Hamiguitan, to which it is endemic, and the Latin ending -ensis, meaning "from". Nepenthes hamiguitanensis is a climbing plant growing to a height of 4 m. The stem is cylindrical and 8–10 mm in diameter in mature plants; internodes are 4–7 cm long. Leaves of the climbing stem are petiolate. The lamina (leaf blade) is elliptic to oblong and measures up to 25 cm in length by 9 cm width.[a] It has an obtuse apex, while the base is gradually attenuate, forming a canaliculate, sessile petiole up to 9 cm long. Three longitudinal veins are present on either side of the midrib. Pinnate veins are numerous and run obliquely to the laminar margin. Tendrils are often approximately the same length as the lamina; those bearing upper pitchers are often curled. In the wild, no adult lower pitchers were recorded, only rosette pitchers on seedling plants. For this reason they were not covered in the formal description. Upper pitchers are infundibular in the basal half and cylindrical to slightly infundibular above. A prominent hip and waist (constriction) delimits these two halves. These aerial traps are up to 20 cm high by 9 cm wide. Wings are reduced to a pair of ribs on the ventral surface of the pitcher cup. The pitcher mouth (≤8 cm wide) has an oblique insertion and rises towards the rear, forming a short neck. The peristome is typically cylindrical but may sometimes be slightly flattened. It is up to 1 cm wide and bears ribs spaced 0.3 mm apart, which terminate in short teeth (≤1 mm long) on the inner margin. The glandular or digestive region covers the lower half of the pitcher's inner surface. The pitcher lid or operculum is cordate and up to 5 cm wide. Nectaries are evenly distributed on the underside of the lid and a prominent appendage is present at the base of the lid's lower surface. A bifurcate spur (≤4 mm long) is inserted near the base of the lid. Upper pitchers are most commonly creamy white throughout, but may also be red speckled on a yellowish background. The peristome may be creamy white, red striped, or dark red. Nepenthes hamiguitanensis has a racemose inflorescence. In the type description, the male inflorescence is recorded as being around 70 cm long by 3.5 cm wide and bearing two-flowered, ebracteate partial peduncles. These measurements are taken from field observations carried out by the describing authors at the type locality on July 23, 2008, since herbarium material of the floral structures could not be located. An coarse indumentum of short, light brown to white hairs is present on all plant parts, being particularly prominent at the laminar margins.