4 . the studies focused on the cnz of dianthus barbatus and saponaria offlcinalis seedlings applied two different vascular cylinder types , even through they both were " " - shape exarch and diarch haplostele , their patterns of protoxylem and m 此外，在商陆科的美洲商陆的子叶节区下部发现了一种具有双大括号状( “ { } ” )的维管柱类型。
