It may be true if one parent was diploid (2 sets of chromosomes) and the other
was tetraploid (4 sets)--in this case, the offspring has 3 sets, and is likely
sterile. If, on the othe hand, both parents have the same number and size
chromosomes, a hybrid *may* be fertile. There are chromosome number indices
on the web in various places--if you know the parents, you may be able to find
information that will help.
>I've just bought a Nepenthes hybrid, and I wanted to know what are the
>consequences of being an hybrid, I mean: as far as I know, the hybrids are
>infertile (cause the chromossomes have no pair). Is this true? So I can't
>propagate it by seed?