The Newick format is used to describe a phylogenetic tree as a string of text. Parentheses are used to group sequence names and branch lengths are included using colons followed by the length. The text string is ended by a semicolon.

An example phylogeny:

   ((Human:0.1,Gorilla:0.1):0.4,(Mouse:0.2,Rat:0.2):0.3);

This describes the following phylogeny:

The topology of the phylogeny is specified by omitting branch lengths:

   ((Human,Gorilla),(Mouse,Rat));