Distinctly different growth phases in apple occurred during the course of development from seed to tree. The juvenile condition was recognized by the thinner leaves with much less pubescence. Anthocyanin production was more abundant in juvenile shoots. In some species of apple, the shape of the leaf changed from an entire to a lobed form with the approach of maturity.
Proceedings of the Iowa Academy of Science
©1937 Iowa Academy of Science, Inc.
Stoutemyer, V. T.
"The Vegetative Growth Phases of Apple Shoots and Their Relation to Root Formation,"
Proceedings of the Iowa Academy of Science, 44(1), 104-105.
Available at: https://scholarworks.uni.edu/pias/vol44/iss1/19