128 
IOWA ACADEMY OF SCIENCES. 
had developed cuticular projections. The moist cultivated 
plants produced slightly thickened epidermal cells, broad cav- 
ities, and no trace of cuticular projections. The sclerenchyma, 
or bast, varies much with different soils and amounts of mois- 
ture. Species of moist, shady habitats, show in their leaves a 
clear preponderance of the assimilating over the mechanical 
system.” 
These views coincide with the observation made in a study of 
the species here considered. 
FESTUCA ELATIOR, VAR. PRATENSIS. 
(PI. lx, Fig. 1; PI. xi, Fig. 9.) 
Epidermis . — The epidermis is quite strongly developed in this 
species; the cuticle is more strongly developed on the inferior 
than superior surface. Small conical projections occur only on 
the superior surface of leaf. These are not very numerous. 
They are most numerous near the carene. The epidermal cells 
are quite uniform in shape; some variations occur, mostly on 
the superior surface. The cells of epidermis over the stereome 
on both superior and inferior surfaces are strongly thickened 
and are smaller than the unthickened epidermal cells. 
BulUform cells . — The bulliform cells are similar in size to those 
found in Lolium perenne. They are five in number, three large 
cells in center and one smaller one on either side. These are 
much more strongly developed toward the middle of leaf than 
on the margin. On approaching the margin of the leaf the 
bulliform cells can hardly be distinguished from ordinary epi- 
dermal cells. 
Mestome bundles .— number of mestome bundles in a single 
cross section in middle of leaf is twenty-four, and are not so 
close as in Lolium. There are three types. First, primary 
type, open on inferior and superior sides. Secondary type, 
those that, are entirely closed, and these are most numer- 
ous. Third, the intermediate type, which are open only on 
superior side. The bundles of secondary type are most numer- 
ous. Three of the closed bundles occur near the margin of leaf. 
One bundle of the primary type is found next to the closed 
bundles. The third type is found to the left of mestome bundle 
of carene, and to the right of carene is found a mestome bundle 
of second type. One primary mestome bundle occurs in carene. 
In the carene leptome and hadrome are well developed. The 
pitted vessels are large. Stereome is well developed on inferior 
