Nortu Haven SaAnp PLaIins 597 
ing matter is found in a few of these cells, but apparently they 
have been developed for water-storage purposes. A large amount 
of this tissue surrounds the midrib. The bundle of the midrib 
is nearly surrounded by two strands of stereome —the larger 
occurring on the leptome side and the smaller on the hadrome 
side. Similar though smaller strands of stereome are found in 
connection with four of the larger mestome bundles, two of these 
having stereome on the leptome side only, while the other two 
have it on both sides of the bundle. Small glandular hairs pro- 
ject from the cuticle on both surfaces. External surface of the 
cuticle is roughened by small projections. Stomata occur on both 
surfaces and are slightly raised rather than depressed. 
IONACTIS LINARIIFOLIUS. — Leaf is thick and rough. The 
entire epidermal layer of both surfaces is composed of colorless 
water-holding cells of uniform size much thickened on the outer 
walls. The thickened cuticle bears short, stout, pointed projections 
having openings into the cells. The two epidermal layers form 
about one third of the thickness of the leaf. A strand of stereome 
occurs on the leptome side of the bundle of the midrib. This is 
the only bundle in which the elements are clearly differentiated, 
though there are eight small mestome bundles in the leaf, four on 
each side of the midrib. On the keel there are three layers of 
nearly colorless, thick-walled parenchyma-cells. The palisade 
layer and mesophyl are very compact. Stomata occur on both 
surfaces, and have a peculiar structure with the cuticle projecting 
over the depressed guard-cells. The projection is slightly raised, 
and appears as a round hole in the leaf when examined from the 
surface (see f/. 26, c). 
ANATOMY OF SUBTERRANEAN Parts 
In the following description of roots the measurements are 
given only for the specimens examined. It should not be inferred 
that the roots are uniform in size or that they have the same num- 
ber of vessels. These measurements are given to show as clearly 
as possible the relation between the size of the root, its central 
cylinder and its largest vessels. 
PANICUM DEPAUPERATUM.— The material examined has eight 
large vessels in the root with nineteen phloem patches arranged 
