152 
IOWA ACADEMY OP SCIENCES. 
on each side. The strongly involute character of the leaf is 
due to the bulliforin cells. 
The carene (c') is occupied with one mestome bundle; this 
bundle is somewhat different than the others, as it is sur- 
rounded on the upper side by chlorophyll bearing parenchyma 
while the lower side contains stereome. 
The mestome bundles on right and left of carene are entirely 
closed (i. e. , entirely surrounded by chlorophyll bearing paren- 
chyma). This species is provided with three different types of 
mestome bundles; the first occurs in carene; this has stereome 
on lower side in contact with leptome; the second, those which 
have stereome both on lowtr and upper side, in contact with 
leptome and hadrome; and third, those that are entirely closed. 
Those that are entirely closed occur alternate with those having 
stereome on upper and lower surface. As to the mestome 
bundles, there are, in this species, five on left side of the carene 
and seven on the right side. On the left, the leaf terminates 
with one closed mestome bundle. The right side of the leaf 
terminates with three mestome bundles. The mestome bundles, 
except those at the tip of the leaf, are separated from each 
other by the bulliform cells and three or four layers of colorless 
parenchyma. The uncolored parenchyma is more conspicuous 
near the median nerve, where it is quite strongly developed. 
In this species the mesophyll does not occur between the 
bundles but is found only in immediate contact with chlorophyll 
bearing parenchyma (c b p). 
The uncolored parenchyma cells are in immediate contact 
with stereome. The mestome bundles are entirely closed and 
do not have leptome (1) and hadrome (h) so well developed as 
in the other bundles. The leptome in the open bundles (i. e. , 
having stereome in contact with both leptome and hadrome) 
seem to be in two parts, there being a depression on upper side 
of leptome. 
The stereome occurs on the upper side of all bundles, and 
also on the lower side of all bundles except those which are 
entirely closed. 
Below the uncolored parenchyma connecting the mestome 
bundles we find the stereome. The stereome occupies a prom- 
inent place on the sides of the leaf, forming on the left two 
triangular groups of cells separated by two layers of uncolored 
parenchyma. On the right side three such groups occur 
between the last four mestome bundles. 
