Observations on growth of long shoots inLarix laricina

摘要

Development of long shoots ofLarix laricina(DuRoi) K. Koch was studied. By the end of the growing season the mature long shoot had both basal and stem needles. All the basal needles were preformed in the unexpanded bud. About half the stem needles were preformed and the rest were initiated during the current growing season. Slight external morphological differences were apparent between oldest preformed and youngest non-preformed needles at maturity. However, since the transition was gradual and all intermediates were present, it was concluded that leaf dimorphism did not occur.