des. x 70

1. Epidermis; 2. sclerenchyma; 3. vascular bundle.]

The stem of _Pennisetum cenchroides_ is somewhat round in outline in the
transverse section with a slight curvature in the front. The vascular
bundles are rather numerous and irregularly scattered all over the
ground tissue. The peripheral bundles are not so close to the periphery
of the stem as in _Rottboellia exaltata_. These are separated from the
epidermis by several layers of parenchymatous cells. Further, these
peripheral bundles are all imbedded in a continuous sclerenchymatous
band which runs round the stem in the form of a ring. The epidermal
cells as well as the layer of cells in immediate contact with it are
thick-walled. In the vascular bundles of the ground tissue the
bundle-sheath is rather prominent and the phloem portion is well
developed. (See figs. 25 and 26.)

[Illustration: Fig. 27.--Transverse section of the stem of Eriochloa
polystachya. x 25]

In the stem of _Eriochloa polystachya_, all the vascular bundles are
more or less peripheral in position leaving a wide area of
parenchymatous cells in the centre. The outline of the stem in cross
section is rotund or ovate-rotund with the front side somewhat flattened
and straight. The epidermal cells alone are thickened. A well developed
continuous ring of sclerenchyma is present and this is connected with
the epidermal layer at short intervals by means of short
sclerenchymatous bands. So the parenchymatous cells of the cortex lying
outside the sclerenchymatous ring are divided into small isolated areas.
There are three series of vascular bundles.

[Illustration: Fig. 28.--Transverse section of a portion of the stem of
Eriochloa polystachya. x 70

1. Epidermis; 2. sclerenchyma; 3. vascular bundle.]

One series consists of small bundles lying inside the sclerenchyma ring
at the base of each of the connecting bands. The second series is made
up of large vascular bundles imbedded in the ring so as to bulge out
inside the ring. The vascular bundles of the third series are found just
away from the ring and separated from it by a few layers of
parenchymatous cells. (See figs. 27 and 28.)

[Illustration: Fig. 29.--Transverse section of the stem of Setaria
glauca. x 15]

[Illustration: Fig. 30.--Transverse section of a portion of the stem of
Setaria glauca. x 50

1. Epidermis; 2. sclerenchyma; 3. vascular bundle.]

Another stem in which the vascular bundles are more or less peripheral
i