Nepenthes spectabilis

Species of pitcher plant from Sumatra

Nepenthes spectabilis /n//ᵻ/'/p//ɛ//n//θ//iː//z// //s//p//ɛ//k/'/t//æ//b//ᵻ//l//ɪ//s/ is a tropical pitcher plant endemic to Sumatra, where it grows at elevations of between 1400 and 2200 m above sea level. The specific epithet spectabilis is Latin for "visible" or "notable".

The first known collection of N. spectabilis was made by Julius August Lörzing in 1920. The specimen Lörzing 7308 was collected on June 5, 1920, on Mount Sibajak at an elevation of 1800 to 1900 m. It is deposited at the Bogor Botanical Gardens (formerly the Herbarium of the Buitenzorg Botanic Gardens) along with two isotypes which include both male and female floral material. A third isotype, sheet H. L. B. 928.350 170, He designated Lörzing 7308 as the type specimen. Danser wrote:

An article authored by Bruce Lee Bednar and published in a 1987 issue of the Carnivorous Plant Newsletter mentions a plant known as N. spectabilis in the horticultural trade. Taxonomist Jan Schlauer considers this plant conspecific with N. curtisii, which in turn is treated as a junior synonym of N. maxima. In their 1997 revision of the genus, Matthew Jebb and Martin Cheek treated specimens of N. lavicola as belonging to N. spectabilis. They also designated Lörzing 7308 as the lectotype of N. spectabilis. The subsequent monograph of Charles Clarke treats these taxa as distinct species. The pitcher lid or operculum is sub orbicular in shape, lacks appendages, and has a strongly cordate base. The spur is very long (≤30 mm) and unbranched. It is inserted near the base of the lid. Certain populations of N. spectabilis differ considerably in morphology. Plants from the type locality produce relatively broad upper pitchers, while those from Mount Pangulubao are much narrower. A particularly gracile form has been recorded from the west side of Lake Toba. Plants from Mount Siluatan are different still, producing pitchers that are green throughout. The species also exhibits great variability in the extent of the indumentum; some plants have a dense covering of hairs, while others are virtually glabrous. In the wild, N. spectabilis is sympatric with N. flava, N. gymnamphora, N. mikei, N. ovata, N. rhombicaulis, and N. rigidifolia. Natural hybrids with all of these species except N. flava have been recorded. Due to the patchy distribution of N. spectabilis, its conservation status is listed as Vulnerable on the 2006 IUCN Red List of Threatened Species.

Nepenthes spectabilis is thought to be most closely related to N. lavicola. It can be distinguished from that species on the basis of its smaller floral bracts, longer fruits, and very long unbranched spur. In Nepenthes of Sumatra and Peninsular Malaysia, Charles Clarke mentions an undescribed taxon from Aceh that is intermediate in appearance between N. lavicola and N. spectabilis. It is unlikely to be of hybridogenic origin as it is not sympatric with any other Nepenthes species. In his 1928 monograph, B. H. Danser placed N. spectabilis in the Nobiles clade. He wrote:

The third group, that of the Nobiles, comprises the species that form a transition between the Vulgatae and the Montanae on one hand and the Regiae on the other. N. spectabilis, from Sumatra, reminds one of N. sanguinea in many respects but shows a resemblance with the Regiae by the yellowish colour of herbarium specimens and by the red brown indumentum. Clarke suggests that N. spectabilis "would perhaps have been better placed in the Montanae, which includes several species that appear to be closely related, such as N. gymnamphora and N. pectinata". In 2001, Clarke published a cladistic analysis of the Nepenthes species of Sumatra and Peninsular Malaysia based on 70 morphological characteristics of each taxon. The resultant cladogram placed N. spectabilis in a small clade with N. gymnamphora. However, since the study was limited in its geographical scope, this placement may not accurately reflect the relationship between N. spectabilis and its closest relatives.

Nepenthes spectabilis occurs sympatrically with many other Nepenthes species and a number of natural hybrids have been recorded.

Nepenthes ovata × N. spectabilis is known to occur along the summit trail of Mount Pangulubao. This hybrid produces pitchers roughly intermediate in appearance between its parent species. The peristome is flattened and expanded, but to a lesser degree than in N. ovata. The speckles of N. spectabilis are present, but the pitchers have a much lighter colouration. Most examples of this hybrid grow terrestrially and some climb into the forest canopy.

Several plants representing the cross N. rigidifolia × N. spectabilis have been recorded from an open rocky outcrop close to the type locality of N. rigidifolia. The hybrid differs from N. rigidifolia in having narrower pitchers with an infundibular base and distinct hip around the middle. On the other hand, the pitchers of this hybrid are broader than those of N. spectabilis and have a wider, expanded peristome. The richly coloured lower pitchers of N. rigidifolia × N. spectabilis superficially resemble those of N. macfarlanei. However, since that species is confined to Peninsular Malaysia, the two taxa are not easily confused.

Four other natural hybrids with N. spectabilis have been recorded. These are N. gymnamphora × N. spectabilis, N. mikei × N. spectabilis, N. rhombicaulis × N. spectabilis, and N. spectabilis × N. tobaica.