Read Tree File in Parenthetic Format

This function reads a file which contains one or several trees in parenthetic format known as the Newick or New Hampshire format.

manip, IO
read.tree(file = "", text = NULL, tree.names = NULL, skip = 0,
    comment.char = "#", keep.multi = FALSE, ...)

The default option for file allows to type directly the tree on the keyboard (or possibly to copy from an editor and paste in R's console) with, e.g., mytree <- read.tree().

`read.tree' tries to represent correctly trees with a badly represented root edge (i.e. with an extra pair of parentheses). For instance, the tree "((A:1,B:1):10);" will be read like "(A:1,B:1):10;" but a warning message will be issued in the former case as this is apparently not a valid Newick format. If there are two root edges (e.g., "(((A:1,B:1):10):10);"), then the tree is not read and an error message is issued.

If there are any characters preceding the first "(" in a line then this is assigned to the name. This is returned when a "multiPhylo" object is returned and tree.names = NULL.


an object of class "phylo" with the following components:edgea two-column matrix of mode numeric where each row represents an edge of the tree; the nodes and the tips are symbolized with numbers; the tips are numbered 1, 2, ..., and the nodes are numbered after the tips. For each row, the first column gives the ancestor.edge.length(optional) a numeric vector giving the lengths of the branches given by edge.tip.labela vector of mode character giving the names of the tips; the order of the names in this vector corresponds to the (positive) number in edge.Nnodethe number of (internal) nodes.node.label(optional) a vector of mode character giving the names of the nodes.root.edge(optional) a numeric value giving the length of the branch at the root if it exists.If several trees are read in the file, the returned object is of class "multiPhylo", and is a list of objects of class "phylo". The name of each tree can be specified by tree.names, or can be read from the file (see details).


Felsenstein, J. The Newick tree format.

Olsen, G. Interpretation of the "Newick's 8:45" tree format standard.

Paradis, E. (2008) Definition of Formats for Coding Phylogenetic Trees in R.

Paradis, E. (2012) Analysis of Phylogenetics and Evolution with R (Second Edition). New York: Springer.

See Also

write.tree,,, scan for the basic R function to read data in a file

### An extract from Sibley and Ahlquist (1990)
cat("owls(((Strix_aluco:4.2,Asio_otus:4.2):3.1,Athene_noctua:7.3):6.3,Tyto_alba:13.5);", file = "ex.tre", sep = "")
tree.owls <- read.tree("ex.tre")
tree.owls <- read.tree("ex.tre", keep.multi = TRUE)
unlink("ex.tre") # delete the file "ex.tre"
### Only the first three species using the option `text'
TREE <- "((Strix_aluco:4.2,Asio_otus:4.2):3.1,Athene_noctua:7.3);"
tree.owls.bis <- read.tree(text = TREE)
Documentation reproduced from package ape, version 3.0-2, License: GPL (>= 2)

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