Nepenthes × kinabaluensis is another impressive plant. The pitchers get large also, but do not compare to those of N. rajah or N. × alisaputrana. It is a well-known natural hybrid of what many consider to be the two most spectacular Nepenthes species of Borneo: N. rajah and N. villosa. Nepenthes × kinabaluensis is only found on Mount Kinabalu (hence the name) and nearby Mount Tambuyukon, where the two parent species are occur sympatrically. More specifically, plants are known from a footpath near Paka Cave and several places along an unestablished route on a southeast ridge, which lies on the west side of the Upper Kolopis River. The only accessible location from which this hybrid is known is the Kinabalu summit trail, between Layang-Layang and the helipad, where it grows at about 2900 m in a clearing dominated by Dacrydium gibbsiae and Leptospermum recurvum trees. Nepenthes × kinabaluensis has an altitudinal distribution of 2420 to 3030 m. It grows in open areas in cloud forest. This hybrid can be distinguished from N. rajah by the presence of raised ribs that line the inner edge of the peristome and end with elongated teeth. These are more prominent than those found in N. rajah and are clue as to the hybrid's parentage (N. villosa has highly developed peristome ribs). The peristome is coarse and expanded at the margin (but not scalloped like that of N. rajah), the lid orbiculate or reniformed and almost flat. In general, pitchers are larger than those of N. villosa and the tendril joins the apex about 1-2 cm below the leaf tip, a feature which is characteristic of N. rajah. In older plants, the tendril can be almost woody. Nepenthes × kinabaluensis has an indumentum of villous hairs covering the pitchers and leaf margins, which is approximately intermediate between the parents. Lower pitchers have two fringed wings, whereas the upper pitchers usually lack these. The colour of the pitcher varies from yellow to scarlet. Nepenthes × kinabaluensis seems to produce upper pitchers more readily than either of its parents. In all respects N. × kinabaluensis is intermediate between the two parent species and it is easy to distinguish from all other Nepenthes of Borneo. However, it has been confused once before, when the hybrid was labelled as N. rajah in Letts Guide to Carnivorous Plants of the World (Cheers, 1992).