Black "squares" in alpha textures. Why?

When I render my scene black squares appear and I don´t want it. How can I avoid it?


It is Cycles by the way.

Increase the max depth for transparency:


You have lined up more transparent planes behind each other than Cycles’ maximum render depth for transparency is set to. From that max depth on the overlapping areas turn out black, as Cycles doesn’t render “through” them any more.

Thank you.