Nananthus transvaalensis (2 pics)

My new plants have arrived! Well, really new are only two, one of which is this Nananthus. I'm still trying to get familiar with more non-lithops mesembs, you know. Not a surprise but still a great sight were the wonderfully thick roots. I read that with the caudiciform mesembs the roots only grow larger when they're underground but I couldn't bring myself to bury them completely (a mistake?). While my Aloinopsis rubrolineata is completely buried (no idea if it helps), Avonia quinaria plants (not a mesemb) are above ground and don't get much bigger as far as I can tell. Maybe I should bury them all for now.

I heard that caudiciforms are grown underground untill they're large enough to be displayed as such...
Thanks for your comment