for N. ventrata no although the N should be since it is the genera name which is part of the scientific name. SO that gives you N. ventrata Most people don't bother with italics every time they write the genera name as it gets to be cumbersome. If you want to be 100% accurate though..
The scientific name for species use italics on both the genera and species name. Except for a few natural hybrids that were described as species originally such as N. x trusmadiensis, note the x is not italicized as it was added later when found to be a natural hybrid. AND a handful of old victorian hybrids like N. x dyeriana
Registered cultivar uses capitals and single quotes such as N. 'Scarlet Splash'
Hope I got that all correct...
Joseph had a sticky thread somewhere on nomenclature which probably goes into more depth.
Tony
Plants which are not officially registered like N. predator are sometimes written like that, or as N. Predator, or as N. "Predator" (note I italicized the N. since it is technically correct but you often don't see it done). There are no formal rules so you most likely will see it written various ways by different people. The only rule is to NOT use the official rules described above for species, natural hybrids described as species, victorian hybrids or registered cultivars....