see here
http://www.pinguicula.org/A_world_of...Pinguicula.htm
some remark
on a lot of hybrids is not possible
all the temperate are a self pollinisate species
the US subtropicale are difficult to pollinised often we must to cut out the corolla to reach the stigmate
on a mexican species to keep all the type caracters without hybridation danger use the leaves cutting.
jeff