Crinum thaianum
Kipp McMichael (Wed, 06 Feb 2013 17:34:02 PST)

Jim,

That's the thing about common names - who knows what they actually reference. My guess for your "onion" plant, as others have mentioned, is Zephyranthes
candida. I have gotten aquarium plants that do smell of onion - and there's no telling what they actually were...

-|<ipp