Hi !!
I read (on Kinabalu Park, visitor's guide of GLOBETROTTER) that high level of iron, silica and metals in the soil is poisonous to many plants, on the contrary Nepenthes can live without problems in this kind of soils. That's why ultramafic soils are typical for some endemism of rare species of Nepenthes and orchids.
Regards
rajah
I read (on Kinabalu Park, visitor's guide of GLOBETROTTER) that high level of iron, silica and metals in the soil is poisonous to many plants, on the contrary Nepenthes can live without problems in this kind of soils. That's why ultramafic soils are typical for some endemism of rare species of Nepenthes and orchids.
Regards
rajah