I have tried quite a few different kinds of plants in ripariums. Among these are some very useful selections. I have also encountered some that were unsuitable for riparium culture, either because they did not adapt to culture in water under artificial lighting, or because their growth habits and shapes were unsuitable for riparium layouts. One group that is especially useful riparium elements are the small herbaceous plants in Genus Pilea. There are several Pilea species that are used as houseplants or terrarium specimens, so they can be found in shops without too much trouble. I have found that the most useful way to employ Pilea plants in ripariums is to plant them on trellis rafts and then position them in the layout midground. They are useful for this because they are relatively short and compact, so they fit well well in front of taller riparium background foliage. These plants have the important advantage of having modest nutrient demands, so they can grow with their roots suspended right in the water and use the nutrients provided in fish waste and modest water column fertilization. Here is a shot of my new 200-litre setups that includes a few very nice little Pilea plants and other light emersed stem plants. There is also an Echindorus sword and some Cyperus umbrella sedge in there. I have started a thread for this setup over in the Journals sub-forum, http://ukaps.org/forum/viewtopic.php?f=35&t=8775&start=40. Here is a close up that shows the two different Pilea in there. Each of these is growing on a nano trellis raft, a foam part that can hold the stems erect and with the bases in the water. The picture below shows the larger of these, which I am identifying with the provisional name, Pilea Florida ditch #1. Here is the smaller plant floating right in front of that one in the tank, Pilea Florida ditch #2. This last picture shows better how the plants grow in the Nano Trellis Raft. The plant here is also a Pilea sp., variety 'Silver Tree'. It has attractive silver-patterned, purple leaves and is the fastest growing Pilea that I have tried. 'Silver Tree' grows so fast that it is necessary to crop the tops of the stems and replant in the trellis raft when it becomes too leggy. The new cuttings root readily when planted in this way.