Leaf gap (lacuna) A region of parenchyma differentiated in the stem vascular cylinder immediately above a diverging LEAF TRACE. Lateral connections insure no break in the vascular system.

• 叶隙：叶迹从中柱分出的上方，初生维管柱上方出现的一些薄壁组织细胞，与茎的维管柱结构不同，它的侧向连接保证了茎叶维管系统的连续。