twins.object

These are objects of class
"twins"
They represent an agglomerative or divisive (polythetic) hierarchical 
clustering of a dataset.

cluster

This class of objects is returned from <code>agnes</code> or <code>diana</code>.

The <code>"twins"</code> class has a method for the following generic function:
<code>pltree</code>.

The following classes inherit from class <code>"twins"</code> :
<code>"agnes"</code> and <code>"diana"</code>.

See <code>agnes.object</code> and <code>diana.object</code> for details.