Glossary of "Plant Biology (1st ed.)" by Graham et al. (2003)
- A young stage of an organism that develops from a single-celled zygote by cell division and differentiation.
Glossary of Plant Systematics (1st ed.) by Simpson (2006)
- An immature, diploid sporophyte developing from the zygote of land plants. (seed part; plant part)
Glossary of "Evolution of Plants (2nd ed.)" by Willis & McElwain (2014)
- A young sporophytic plant.
- Graham, L. E., Graham, J. M. & Wilcox, L. W. 2003. Plant Biology. -xxxv + 497 pp. Pearson Education, Inc., Upper Saddle River.
- Willis, K. J. & McElwain, J. C. 2014. The Evolution of Plants, 2nd ed. -ix + 398 pp. Oxford University Press, Oxford.