A list of trees, of class list,
multiPhylo, or, if a single tree,
phylo.
Value
UnshiftTree() returns a list of class list or multiPhylo
(following the original class of treeList), whose first element is the
tree specified as `add.
Details
Caution: adding a tree to a multiPhylo object whose own attributes apply
to all trees, for example trees read from a Nexus file, causes data to be
lost.