Extending 'dendrogram' Functionality in GNU R

 Offers a set of functions for extending 'dendrogram' objects in R,
 letting you visualize and compare trees of 'hierarchical
 clusterings'. You can
 .
  (1) Adjust a tree's graphical parameters - the color, size, type, etc
      of its branches, nodes and labels.
  (2) Visually and statistically compare different 'dendrograms' to
      one another.