The format is:
List of 5
$ edge : int [1:72, 1:2] 38 39 39 40 41 42 42 43 44 45 ...
$ Nnode : int 36
$ tip.label : chr [1:37] "Ips_acuminatus" "Ips_duplicatus" "Ips_integer" "Ips_plastographus" ...
$ edge.length: num [1:72] 0.2806 0.0727 0.0295 0.0097 0.021 ...
$ node.label : chr [1:36] "" "100" "21" "12" ...
- attr(*, "class")= chr "phylo"
- attr(*, "order")= chr "cladewise"