[R] help on drawing a tree with "ape"?

[Hua Li]

Dear all,

I'm using the "ape" package in R and want to draw a
phylogenetic tree with not only the tip labels but
also some labels for the edges. e.g. Mark the edge AB
as "m" in the tree ABC.  

Couldn't find a way to do that. Can someone help?

Thanks,

Hua