tikz-qtree: curved lines & multiple parent nodes

Question

I am quite new to LaTeX, and I am stuck with a problem Google can't seem to help me with. Basically, I need some hand holding in doing something that is more complicated than my skills can handle at this moment.

Basically, what I want to do is this:

I can currently get as far as the tree shown on the right side of the image above, using the following code:

\documentclass{article}
\usepackage{tikz-qtree}
\usepackage{upgreek}
\begin{document}

\begin{tikzpicture}
    \Tree [ [ \node(onset){r}; ] [ \node(mora1){e}; ].$\upmu$ [  ].\node(mora2){$\upmu$}; ].$\upsigma$
    \draw (mora1) -- (mora2);
\end{tikzpicture}

\end{document}

However, that's the best I know how to do. What I still need:

• how do I draw a curved line instead of a straight one?
• most importantly, how can I make two parent nodes share one child node, without it looking like crap as it does now?

I realize these may be noobish questions, but please understand that I did try Googling my problem and I just couldn't find the information I needed. The full TikZ manual is way over my head, and the tikz-qtree manual doesn't cover my case.

Thanks very much for any pointers you can give me.

Answer 1

As Andrew notes, autosegmental representations of the sort you are drawing aren't really trees. If you are likely to be drawing a lot of these, you might want to investigate the very powerful (but also very complicated) pst-asr package.

In the meantime, here's a hybrid approach using tikz-qtree but positioning the segmental tier manually using TikZ's scope mechanism.

\documentclass{article}
\usepackage{tikz-qtree}
\usetikzlibrary{positioning}
\usepackage{upgreek}

\begin{document}

\begin{tikzpicture}[level 1/.style={sibling distance=.75cm}]
\Tree [.\node (syll) {$\upsigma$}; [.\node(m1) {$\upmu$}; ] [.\node (m2) {$\upmu$}; ] ]
\begin{scope}[yshift=-2cm]
\node (e) {e};
\node (r) [left=1cm of e] {r};
\draw (e.north) -- (m1);
\draw (e.north) -- (m2);
\draw (r.north) edge[out=90,in=180] (syll.south);
\end{scope}
\end{tikzpicture}

\end{document}