All four species of Australian pitcher plants are early in the process of evolutionary divergence. Hybrids and introgressed taxa are very common in the floodplains of Cape York where multiple species grow in close proximity.
Nepenthes tenax x Nepenthes rowaniae
Nepenthes tenax x mirabilis
N. tenax confers upright pitchers that are held above the petiole, and yellow-green colouration. N. mirabilis confers broader leaves, long internode length, extra spiral and twining on the tendril, and an obvious pitcher hip.
Nepenthes rowaniae x mirabilis
Nepenthes parvula hybrids
The exact parentage of Nepenthes parvula hybrids are difficult to ascertain. Traits consistent with introgression from N. mirabilis and N. tenax include obvious pitcher hips, comparatively larger size and coiling tendrils. Complex hybrids between these three taxa, but morphologically tending towards N. parvula are common in the field.
Complex Nepenthes Hybrids
Widespread hybridisation and repeated backcrossing can lead to some interesting morphologies, including this very squat specimen.