You must use Thunder on the cactus. Then continue with the fire on the mushroom and the blizzard on the three stones (I think you have to hit them from smallest to largest) and finally use holy on the strange flower, found on the left side of the stage. And all these events are in the beginning scene. If the screen turns black, then you know you have to go back.

I had explained the same thing in another thread I made, but I can't seem to find it anymore. Anyways, this is the secret of the lynari desert.

The reward is the secret element set into your chalice.