Between primary xylem and primary phloem there are 2& 3 layers of parenchymatous cells, regularly or irregularly arranged, but no cambial zone can be recogni-zed.
初生木质部与初生韧皮部之间可见到2&3层排列规则或不规则的薄壁组织细胞,但是没有维管形成层的发生。
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