[Rod Porteous]

I have no information on the use of walnut trees, but the catappa (Seemandelbaumblätter) trees are unlikely to be part of the Parosphromenus ecosystem, as they are mainly found along the coast. I doubt the tree would be able to survive in a peat swamp. The use of catappa leaves probably came about because they are grown as ornamental specimens in many towns and villages in south east asia especially Thailand, and the leaves were easy to come by.