PHYLIP is an extensive and widely-used package of programs for inferring phylogenies. It contains over thirty different algorithms for constructing phylogenic trees. Although many of them are designed to work with molecular sequence data, several general methods accept arbitrary distance matrices as input. With versions written in C and Pascal, and binaries for Windows, DOS, Macintosh, and PowerMac, it is available on the WWW from http://evolution.genetics.washington.edu/phylip.html.