IOWA ACADEMY OP SCIENCES. 
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(m) of the second type connecting these bundles with the 
stereome. 
SPOROBOLUS VAGINAEPEORUS. 
In this species the epidermis (e) resembles that of other 
species except the cuticle (c) which is much more fully devel- 
oped. 
The bulliform cells (b) in this species differ much from those 
of other species, they are very irregular in outline, the cells 
ranging in number from eight to ten, and occur almost the 
entire length of the leaf except near the sides where we find 
the uncolored parenchyma (p). 
The carene (c') consists of one mestome bundle which has 
stereome in contact with leptome (1). This is the only bundle 
which is open. On either side of this median bundle there 
are three or four small closed bundles. The leptome and had- 
rome (h) are separated by thick walled parenchyma. The 
mestome bundles number twelve, five to the left and six to the 
right of the carene. The bundles are of two types: first the 
median one which is open below and the second, closed; 
the bundles of this latter type are of two sizes, one very much 
smaller and the other nearly as large as that of the median 
nerve. The well developed leptome and hadrome in the median 
nerve and the larger bundles of the second type are character- 
istic. The smaller mestome bundles predominate, numbering 
nine in a leaf. The sterome occurs on upper and lower sur- 
face of the mestome bundles of the carene, and large sized 
mestome bundles of second type, but none are found in contact 
with smaller sized bundles. 
The cells of the chlorophyll bearing parenchyma (c. b. p.) in 
this species are much smaller than the cells of the other 
species. 
The uncolored parechyma (p) is found only at the edges of the 
leaf above the last two mestome bundles. 
PANICUM. 
The large genus Panicum is widely distributed in tropical 
and warmer countries with a goodly number in temperate cli- 
mates. The representatives studied by us are common species 
in the Mississippi valley and southward. The three species, 
P. capillare L., P. proliferum L., andP. crus-galli L , grow in 
moist places or where there is considerable rainfall. The 
weedy P. capillare is perhaps an exception, as it is adapted to 
a wider range of climatic conditions, the structure of the leaf 
