Annual ring (growth ring) The annual increase in girth of the stems or roots of woody plants, as a result of cambial act年轮：木本植物形成层的活动随着季节的更替而表现出有节奏的变化。
Procambium (procambial strand) The layer of cells that gives rise to the vascular tissue.原形成层（原形成层束）：形成维管组织的一层细胞。
The leaf axis arises from the leaf buttress and maintains procambial continuity in the central region.叶轴也来自叶原基和在中央区保留的原形成层细胞。