IOWA ACADEMY OP SCIENCES. 
133 
The uncolored parenchyma cells which occur below and to the 
side of the middle carene bundle, are large. These cells are in 
contact with the three large bundles of the carene (Car.) The 
smaller mestome bundles (M) on either side of the carene occur 
close together. The chlorophyll-bearing parenchyma cells 
(C.B.P.) surrounding them are conspicuous. These bundles 
are not uniform in number on both sides of the mid- rib, which 
goes to show that the development of the leaf is unequal. On 
each side of the carene occur four of the larger secondary 
bundles. 
The edges of the leaf are provided with stereome (Ste.) The 
stereome about the bundles varies in the number of cells. 
The cells of the mesophyll (Mes.) occur as dense masses with 
numerous intercellular spaces. They vary in shape from elon- 
gated to spherical. An occasional small trichome (Tri.) (Fig. 
4) may be seen. 
ANDROPOGON NUTANS. 
(PI. xii, Figs. 1 and 5; PL xv, Figs. 14 and 15.) 
In this species, as in A. provincialis, the epidermal cells (E.C.) 
are large, nearly round and vary in size. The cuticle (C) is 
well developed. The conical projections (C. P.) are conspicu- 
ous, and more so on the lower than on the upper surface. 
Th bulliform cells (B. C.) vary in number from two to five. 
They ai e more uniform in number than A. provincialis^ and do 
not vary so much in size. They occur between the secondary 
veins and below the smaller closed mestome bundles (M). In 
this species, as in A. provincialis, occur four types of bundles, (1) 
carene, (2) entirely closed by surrounding chlorophyll-bearing 
cells, (3) open, (4) large bundles with leptome (L.), and hadrome 
(H.), more strongly developed. There occasionally occurs a 
short and sharply pointed trichome emerging from the mes- 
tome bundle of the secondary vein. The secondary bundles are 
open above and below. Stereome (Ste ) occurs on both sides of 
these bundles. 
The carene differs from that of A. provincialis in the number 
of pitted and spiral ducts. Its parts are all well developed. 
The stereome below the carene is not so abundant as in A. 
provincialis, but the reverse is true of the stereome above the 
carene. The uncolored parenchyma cells between the bundles 
and upper stereome are more numerous than in A. p)rovincialis. 
The mestome bundles are not so close together in this spe- 
cies as in A. provincialis. The larger bundles vary in number 
