I seem to remember that Prayer Plants (Maranta leuconeura) are very intolerant
of fluorine. We were always instructed to avoid perlite in their potting mix
for this reason.
>I'm doing a research project on the effects of fluoride-treated water on
>plants. Can anyone please suggest what kind of plants to use -- small
>and cheap, that would work well for this experiment? Also, what range of
>fluoride concentrations would be best to test?