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> Water control in a succulent plant:
> 
> https://www.sciencedaily.com/releases/2024/07/240703131733.htm
> 
> [The]..."Department of Mechanical Engineering of PolyU, has discovered that the succulent plant Crassula muscosa, native to Namibia and South Africa, can transport liquid in selected directions.
> 
> "...the PolyU researchers noticed that when two separate shoots of the plant were infused with the same liquids, the liquids were transported in opposite directions. In one case, the liquid travelled exclusively towards the tip, whereas the other shoot directed the flow straight to the plant root. Given the arid but foggy conditions in which C. muscosa lives, the ability to trap water and transport it in selected directions is a lifeline for the plant.
> 
> "As the shoots were held horizontally, gravity can be ruled out as the cause of the selective direction of transport. Instead, the plant's special properties stem from the tiny leaves packed onto its shoots. Also known as "fins," they have a unique profile, with a swept-back body (resembling a shark's fin) tapering to a narrow ending that points to the tip of the plant. The asymmetry of this shape is the secret to C. muscosa's selective directional liquid transport. It all has to do with manipulating the meniscus -- the curved surface on top of a liquid.
> 
> "Specifically, the key lies in subtle differences between the fin shapes on different shoots. When the rows of fins bend sharply towards the tip, the liquid on the shoot also flows in that direction. However, on a shoot whose fins -- although still pointing at the tip -- have a more upward profile, the direction of movement is instead to the root. The flow direction depends on the angles between the shoot body and the two sides of the fin, as these control the forces exerted on droplets by the meniscus -- blocking flow in one direction and sending it in the other."
> 
> Comment: the plant does not have a brain with which to produce this mechanism. I can't imagine the plant developing this by chance in the desert. Assuming the plant started to live in a wetter climate that then became more arid, it would have to develop this fabulous engineering by trial and error. Not likely. Design is the answer.