Creating a list in Org from a Ruby Array is trivial

#+BEGIN_SRC ruby :exports results :results value list
["x" , "y", "z" ] 
#+END_SRC

#+RESULTS:
- x
- y
- z

But trying the same thing from R gives a surprising (to me) result

#+BEGIN_SRC R :exports results :results value list
c("x","y","z")
#+END_SRC

#+RESULTS: 
- ("x")
- ("y")
- ("z")

removing the list header creates a table, but there seems to be no straightforward way in R to create a list of elements that is treated by Org as a list.  Am I missing something?

Greg