Realy? Pervillei is not cross fertile and could be in a genus of it`s own? Thats cool! Have any photos\links to photos of this plant? Is it known wether the reason is because of uncompatible chromasome counts?(and if so has someone colchine treated some seed to produce crossable pervillei?).Are the physical differences in this plant enough to warrant seperate genus classification?
Are there other non-cross fertile Nepenthes? This is interesting stuff Thank you for sharing Hamish(what a neat name for a Nep enthusiast).