In the developmental biology of tissue animals , the term cotyledon is the first differentiation of an embryo into different cell layers , from which different structures, tissues and organs subsequently develop. The cotyledons arise from the blastula during gastrulation .
The transformation of cells from one cotyledon into cells of another is called transdifferentiation .
- Cleveland P. Hickman, Allan Larson, Larry S. Roberts, David J. Eisenhour: Zoology . Pearson Germany, Hallbergmoos 2008, ISBN 978-3-8273-7265-9 , pp. 245-246 .