Terminal vessel and early vessel arrangement in internodes of Fraxinus excelsior.

Application of auxin to the apical end and to the transverse incision in a dissected internode. led to the formation of early vessels in such a way thai the vessels below the incision were abgned with the vessels above it. Thcre was a structural relation between the early vessels and terminal vesscls based on the fact thai the former overlay the latter. A hypothesis is forwarded stating that a template according to which the early vessels find their positions. exists on the surface of terminal wood