Wedgestalk

The wedgestalk replaced its ancestor the marsh-column stalk. Its main adaptation is its new wedge shaped trunk. This allows any water which flows past it during the flood season to flow past it. Like its ancestor it grows a side fan at its underwater part of the stalk that faces the stream. Using movement sensors in this fan when an object comes its way down the stream the fan starts moving back and forward making it stray to the sides of the plant. The fan shrinks and dies after this season is over.

Its roots have gotten stronger and grow in hooked shapes in order to grasp rocks within the ground so it will not get uprooted from anything that knocks into it during the flood season. In fact it has gotten so good at live in the flooded waters that some live in their full time and never loose their fan leaf.