The short shoot, an indicator of beech maturation (Fagus sylvatica L.)

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.