126 
IOWA ACADEMY OF SCIENCES. 
A COMPARATIVE STUDY OF THE LEAVES OF 
LOLIUM, FESTUCA, AND BROMUS. 
BY EMMA PAMMEL, 
There are some striking differences in the leaves of Festuca 
and Lolium. One of the most essential in the species studied 
is the presence or absence of hairs and the involute character 
of the leaf of Festuca tenella. 
LOLIUM PERENNE. 
(PL ix, Fig. 3; PL xi, Fig. 8.) 
Eindermis.—'Th.e cuticle is quite-strongly developed on super- 
ior and inferior surfaces of the leaf, but more so on the inferior 
surface. The epidermal cells are rather large, but vary some 
in size; the largest occur on inferior surface of leaf and are 
nearly as large as the bulliform cells. The smallest epidermal 
cells occur chiefly at the tip of leaf. The epidermal cells above 
and below the stereome are smaller and are strongly thickened. 
Bulliform cells . — The conspicuous bulliform cells number 
from four to five. The central are large and one or two on 
either side occur between each mestome bundle. The epider- 
mal cells on the inferior surface of leaf are more uniform in 
size. 
Mestome bundles . — These number eighteen, of three types. 
Primary bundles, those which are open on superior side of leaf, 
i. e . , where hadrome is either in direct contact with stereome 
or separated from it by colorless parenchyma cells, and secon- 
dary bundles or such as are closed, i. e., the leptome and had- 
rome entirely surrounded by chlorophyll-bearing parenchyma; 
and third the intermediate type. The secondary mestome bundles 
are more numerous. The leptome and hadrome of the mestome 
bundle of carene are well developed. The mestome bundle of 
carene is of the primary type with well developed pitted ves- 
sels and spiral ducts. Two rows of thick-walled cells separate 
hadrome and leptome. The hadrome is separated from the 
