Re: Mysterious Tiny Plant

The plant you have is certainly a species of Wolffia. Landolt (1987) in 
his monograph on the Lemnaceae lists 9 species. It is interesting that 
you have it growing in your tank since they prefer hard water (Im 
assuming that is not the situation in your tank?). What is even more 
interesting is that you have flowers! Wolffia is VERY difficult to bring 
to flowering. For my PhD I studied the Lemnaceae for almost four years. I 
grew mostly Lemna trisulca but did also have Wolffia sp. and try as I 
might I could not induce it to flower (maybe it was all those cool white 
bulbs I was using). Take pictures!

Dr. dave