not. Finally, N. angasanensis exhibits a greater density of digestive glands on the inner pitcher surface. Nepenthes angasanensis and N. mikei are more easily distinguished by their differing ecology. While N. angasanensis is generally found growing terrestrially or epiphytically in shady mossy forest, N. mikei is always terrestrial and favours more exposed sites where it receives strong sunlight. Nepenthes angasanensis also typically produces longer stems, with regular offshoots from the leaf axils, although these have been observed in N. mikei as well. Nepenthes tobaica differs from N. mikei in a number of floral and vegetative features. Whereas the latter has a shorter inflorescence with flowers borne singly on pedicels, N. tobaica has two-flowered partial peduncles. In addition, N. tobaica lacks the fasciculate spur of N. mikei and generally has wider laminae. Salmon and Maulder also compared N. mikei to N. adnata and N. tentaculata. Stewart McPherson noted that the species may also superficially resemble N. eustachya in the shape of its pitchers. In 2001, Charles Clarke performed a cladistic analysis of the Nepenthes species of Sumatra and Peninsular Malaysia using 70 morphological characteristics of each taxon. The following is a portion of the resultant cladogram, showing part of "Clade 6". The sister pair of N. angasanensis and N. mikei has 79% support. Clarke concluded that the "relationships between [these species] are very complex and are somewhat difficult to interpret at present". Natural hybrids Four natural hybrids involving N. mikei have been recorded. N. diatas × N. mikei Nepenthes diatas is restricted to Mount Bandahara and thus this hybrid only occurs on that mountain. This cross is common between 2300 and 2700 m, where the altitudinal ranges of the two species overlap. It was first reported in 1998. This hybrid is similar to N. mikei and also produces mostly black lower pitchers. It differs in that the terrestrial traps have a wider basal portion. The plant is also larger in stature, having broader stems and leaves, and bears a wider peristome than N. mikei. Nepenthes diatas × N. mikei has only been found at the forest margins in the summit area of Mount Bandahara. It has not been recorded from the mountain's open blangs. Other hybrids Three other natural hybrids — with N. gymnamphora, N. ovata, and N. spectabilis — have been observed. All three were first reported in 1995 by Salmon and Maulder from Mount Pangulubao. Nepenthes gymnamphora × N.