Glossary of "Plant Biology (1st ed.)" by Graham et al. (2003)
- The embryonic seed leaves in flowering plants that contain the nutritive tissue derived from the endosperm.
Glossary of "Plant Systematics (1st ed.)" by Simpson (2006)
- A first (seed) leaf of the embryo, often functioning in storage of food reserves. (seed part)
Glossary of "A Botanist's Vocabulary" by Pell & Angell (2016)
- Graham, L. E., Graham, J. M. & Wilcox, L. W. 2003. Plant Biology. -xxxv + 497 pp. Pearson Education, Inc., Upper Saddle River.
- Simpson, M. G. 2006. Plant Systematics. -xi + 590 pp. Elsevier Academic Press, Oxford.
- Pell, S. K. & Angell, B. 2016. A Botanist's Vocabulary: 1300 Terms Explained and Illustrated. 226 pp. Timber Press, Portland.