Odersky himself has implied that Scala was prompted by Clojure in its recent persistent structure implementations. However, this influence is motivational rather than via copied code (as stated at http://stackoverflow.com/a/3108380). Although Odersky does mention the word "copied" in an interview that I had with him, but that state of affairs may have changed (http://blog.fogus.me/2010/08/06/martinodersky-take5-tolist/).
My guess was that it was going to be the container library, rather than the language itself. If libraries are included, then Clojure-inspired HAMTs are in Haskell as well. But really, Clojure, Haskell and Scala are all just implementing Bagwell's ideas, http://lampwww.epfl.ch/papers/idealhashtrees.pdf whose feasibility was shown in Clojure.
However, your graph will be much more complicated if libraries are allowed to influence each other, rather than strictly considering language features.
> My guess was that it was going to be the
> container library, rather than the language itself.
This walks a thin line for sure and in Scala the line is almost microscopic. I'll keep it for now since my reasoning was the same as the Erlang->Scala influence. A core language library that is rarely viewed as other than a core feature.
