I recently purchased 4 cardinal plants for my tank. They're got dark green leaves that have purple undersides. The little stick in the plants said "Lobelia cardinalis" and also that it was a "true aquatic" plant. I've seen some posts here & on other sites where people have had success with them (though they may eventually grow all green and lose the purple color), while others had them die off because they're NOT a true aquatic. I know there is another plant sold in the aquarium trade that's sometimes known as the cardinal plant, but its scientific name is different - Hemigraphis something-or-other. My plants seem to be doing well so far (it's only been about a month since I planted them) and are putting out new growth. Can anyone give me the correct info on this particular type of "cardinal plant?" I'd appreciate any advice. Thanks!