Glossary of "Cladistics (2nd ed.)" by Kitching et al. (1998)
- (1) A scored observation of a feature perceived in the organism(s) chosen to represent a terminal taxon. (2) One of two or more alternative manifestations of a character (2).
Glossary of Plant Systematics (1st ed.) by Simpson (2006)
- One of two or more forms of a character.
Glossary of "Evolution (3rd ed.)" by Futuyma (2013)
- One of the variant conditions of a character (e.g., yellow versus brown as state of the character "color of snail shell").
- 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.
- Simpson, M. G. 2006. Plant Systematics. -xi + 590 pp. Elsevier Academic Press, Oxford.
- Futuyma, D. J. 2013. Evolution, 3rd ed. -xviii + 656 + 14 + 37 + 2 + 36 pp. Sinauer Associates, Inc., Sunderland.