part of the parenchymatous bundle sheath or the outer layer of the
occur in stegmata overlying sclerenchymatous vascular bundle sheaths,
sclerenchymatous bundle sheaths, while Zingiberaceae have predominantly
marks only one variation among others with similar function, such as the starch sheath in the stem and the bundle sheath around foliar vascular bundles.
in the form of a narrow ribbon but that other anatomical specializations of the bundle sheath (endodermis) cell wall occur in some taxa.