Glossary of "Cladistics (2nd ed.)" by Kitching et al. (1998)
- A branching diagram on which teh length of each branch is proportional to the amount of character change that occurs along it. See also non-metric tree, ultrametric tree.
- Kitching, I. J., Forey, P. L. Humphries, C. J. & Williams, D. M. 1998. Cladistics, 2nd ed.: the Theory and Practice of Parsimony Analysis. -xii + 228 pp. Oxford University Press, New York.