Fig. 30.—Transverse section of a portion of the stem of Setaria glauca. × 50
1. Epidermis; 2. sclerenchyma; 3. vascular bundle.
Another stem in which the vascular bundles are more or less peripheral in position and enclosing a wide parenchyma is that of Setaria glauca. In the transverse section of the stem the outline is ovate, laterally compressed, obtusely keeled at the back and somewhat concave in the front. The sclerenchymatous band is narrow and continuous and very close to the epidermis, being separated from it only by two or three layers of thin-walled cells. The epidermal cells alone are thickened. As to the vascular bundles there are three sets. One set of bundles lying just outside the sclerenchymatous ring consists of small ones connecting the ring with the epidermis. Just inside the sclerenchymatous ring lies a series of bundles which are connected with it. Still inside, at some distance from the sclerenchymatous band, are seen vascular bundles forming a row and enclosing a large space of the ground tissue consisting of only parenchyma. (See figs. 29 and 30.)
Fig. 31.—Transverse section of the stem of Panicum ramosum × 24