The cells of the bundle sheath that surround the vascular tissues are large and contain specialized elongated chloroplasts that do not contain grana, but form starch grains.

• 它的特点为：围绕在维管组织外层的维管束薄壁细胞较大，并含有较大的叶绿体，这些叶绿体中不含基粒，但形成淀粉粒。