How do I align vertical trees to to the top?
This is my current tree: I want to get this tree:

^ That's a part of my current tree
I'm trying to create a graph which illustrates a path algorithm of O(N!). For readability, I only show descendants for the top node, all of the lower nodes should be postfixed by a fork- / rake-like object.
I'd appreciate an answer which shows the correct solution, plus an explanation of the used code.
My relevant code:
\documentclass[12pt,a4paper]{article}
\usepackage{tikz-qtree,tikz-qtree-compat}
\begin{document}
\begin{tikzpicture}
\tikzset{grow'=right,level distance=50pt}
\tikzset{execute at begin node=\strut}
\tikzset{every tree node/.style={align=left,anchor=base west}}
\Tree [.\node(root){E};
[.A \node(x){R};
[.D ]
[.U ]
[.T ]
]
[.R ]
[.D ]
[.U ]
[.T ]
]
[.R ]
[.D ]
[.U ]
[.T ]
]
\draw[->](x)..controls +(north west:1.5) .. (root);
\end{tikzpicture}
\end{document}

Rif I write[ .R{\,$\cdots$} ]in the descendents ofE. – egreg Jan 13 '12 at 11:32