I am growing (barely) M. thailandicum. It seems to take perfect drainage with twice daily misting. Not sure on your spelling question ..rum vrs ..rium. I usually use rium. Check Fern Grower's Manual by Hosizaki & Moran for the definitive answer.

Hi
Thanks for the info. From what I've found UM is the correct spelling though i found references to another genus using ium lol though they mentioned it was mis spelled lol.
I recently got one labeled M.steelei thought it looks identical to one i know as M.thailandicum.At least to me.
I'm growing both in deep shade with N.Z. sphagnum moss

The thailandicum is growing well but not anywhere near the 24 inches i've read about Have only had the steelei about a month The M. musifolium is responding very well to the same conditions. So guess i will have to wait and see.
I grow the M. pteropus submerged in water on drift wood and is doing very well but want to grow emerged if possible . May try a marsh area. Seems to tolerate a lot of light even dirct sun.
Thanks again for the reference . Will check them out.
gary