Nepenthes Fusca - Related Species

Related Species

Among the closest relatives of N. fusca are the Bornean species N. epiphytica, N. hurrelliana, N. platychila, N. stenophylla, and N. vogelii. More broadly, it belongs to the loosely defined "N. maxima complex", which also includes N. boschiana, N. chaniana, N. eymae, N. faizaliana, N. klossii, and N. maxima. The enigmatic N. mollis, which some authors have suggested is conspecific with N. hurrelliana, may also be closely allied.

The lower pitchers of N. hurrelliana are distinctive, but the upper ones bear a close resemblance to those of N. fusca. Of the Bornean pitcher plant flora, only these two species have such a narrowly triangular lid. The upper pitchers of N. hurrelliana differ in having a horizontal mouth that rises abruptly into a long neck at the back and in having a hirsute basal crest on the underside of the lid.

Nepenthes hurrelliana is particularly similar to a form of N. fusca from the southern portion of the Crocker Range in Sabah. This form exhibits a wider peristome, longer neck, and a more triangular lid than most other examples of the species. However, the peristome is still not as well developed as in N. hurrelliana and the plant lacks the dense indumentum of the latter. Furthermore, N. hurrelliana differs in the distribution of nectar glands on the lower surface of its lid.

The first known collection of N. vogelii, made in 1961, was labelled as N. fusca. In 1969, botanist Shigeo Kurata examined this specimen and noted that it did not fall within the known variation exhibited by N. fusca. Nevertheless, the species remained undescribed until 2002. Nepenthes vogelii differs in having much smaller pitchers and lacking appendages on the underside of the lid. In addition, the lid of N. vogelii is broadly triangular as opposed to the narrowly triangular lid of N. fusca. The colour of the pitchers—light cream with dark speckles—is also distinctive.

Nepenthes faizaliana also bears a resemblance to N. fusca. In their description of the former, J. H. Adam and C. C. Wilcock distinguished these taxa on the basis of inflorescence structure, the size of the glandular region on the inner surface of upper pitchers, and the development and characteristics of the indumentum. In addition, N. fusca differs in having a very narrow pitcher lid, as opposed to the orbicular lid of N. faizaliana.

Nepenthes platychila can be distinguished from N. fusca on the basis of its much wider peristome and lid, the latter lacking appendages on its lower surface. Nepenthes fusca is also thought to be closely related to Sulawesi's N. eymae, and N. maxima, which is widespread in Sulawesi, New Guinea, and the Maluku Islands.