In beech, no external morphological characters that allow an understanding
of how an individual stem gradually and continuously evolves from a juvenil
e vegetative stage toward a mature flowering stage, has ever been demonstra
ted. The only known traits are marcescence, indicating a juvenile stage, an
d flowering, indicating passage to adult stage. However, in young trees gro
wing under a forest shadow, these markers are not visible since marcescence
is not expressed and the trees are too young to flower. This study was con
ducted to find one or more external morphological characters that indicate
the state of differentiation in beech. For that purpose, a simultaneous des
cription of tree architecture and the short, 1-year-old, foliated growth un
its (u.c.) of the trees was completed. Analysis showed that the morphology
of short u.c.'s evolved according to their localization in the plant, the a
ge of the plant, and the environment where in which it is developping. Anal
ysis also revealed that this evolution was directly related to growth in he
ight of trees, but also and above all, to the degree of complexity reached
during the trees' development. Thus, evolution of short u.c.'s is a scale o
n which some traits expressing internal plant potentialities (marcescence,
flowering) can be localized.