[pstricks] pstree colored boxes

[Olga Lyashevska]

Dear list,

I would like to fill boxes at the end of each branch with a grey color.
Could you please suggest anything?

Thanks in advance,
Olga

---------------------begin example-----------------

\documentclass{article}
\usepackage{graphics, graphicx}
\usepackage[usenames,dvipsnames]{pstricks}
\usepackage{pst-node, pst-tree}

\newcommand{\Itemf}[1]{\Tr[ref=l]{%
\psframebox[linestyle=solid,fillstyle=solid]{#1}}}

\begin{document}

\renewcommand{\psedge}{\ncangle}
\psset{xbbd=1.5cm,treemode=R,angleB=180,angleA=-00,levelsep=72pt}
\pstree{\Itemf{Descriptor}} {%
   \pstree{\Itemf{Number}}{ \pstree{\Itemf{Richness}}{\Itemf{a
diversity}\Itemf{...}}
   \Itemf{...}}
    \pstree{\Itemf{Feature}}{\Itemf{Phenotype}\Itemf{Morphology}\Itemf{Gen.
Homology}}
     \pstree{\Itemf{Pattern}}{\Itemf{Composition}\pstree{\Itemf{Evenness}}{\Itemf{Frequency}\Itemf{Dispersion}}
          \pstree{\Itemf{Abundance}}{\Itemf{Rarity}\Itemf{...}}}
     \pstree{\Itemf{Distance}}{\Itemf{b diversity}\Itemf{...}}
    \pstree{\Itemf{Function}}{\Itemf{Interaction}\Itemf{Process}}%
}
 \end{document}

---------------end example--------------