134 BOTANICAL GAZETTE [FEBRUARY 
cially in the larger ones. In regard to the mechanical tissue, a stere- 
ome occurs in large groups, one in each margin of the blade, besides 
smaller groups accompanying the nerves, and located above and 
below them between epidermis and palisades. 
Characteristic of Munroa and several of its associates among the 
Gramineae are the nearly orbicular mestome bundles surrounded by 
the single layer of straight-walled palisades, radiating from them and 
bordering on a rather large-celled parenchyma sheath, inside of which 
a typical mestome sheath occurs; and also the deeply furrowed blade 
with bands of bulliform cells covering strata of colorless tissue, the 
function of which is evidently to store water. The numerous epi- 
dermal projections in the shape of papillae or long-pointed spines 
partly surround and cover the stomata. 
THE PROPHYLLON.—This very characteristic leaf, as stated above, 
consists of a sheath-like, bicarinate, membranaceous body and two 
long setae, the nerves being extended beyond the apex of the leaf. 
The structure of the sheath-like portion is very simple, since the 
margins and the central part possess only an epidermis (the dorsal) 
with a few stereomatic cells scattered here and there. The two keels, in 
which two mestome bundles are located, show a more solid structure, 
since each keel has a support of quite thick-walled stereome, which 
borders on a large-celled, colorless parenchyma. Each mestome 
bundle has a closed parenchyma sheath and a moderately thickened 
mestome sheath. The awns contain chlorophyll, located in a stratum 
of palisades and in the parenchyma sheath, and stomata occur on 
the upper surface. A cross-section of one of these awns is sharply 
triangular, with the two lateral angles occupied by stereome, while 
the keel contains a large mass of colorless parenchyma. The mestome 
bundle is located in the center, but is very small and consists only of 
leptome. 
THE FLOWERING GLUMES AND THE PALETS.—As stated above, the 
glumes of the terminal spikelet are somewhat different from those of 
the lateral in regard to shape and texture, and therefore the spikelets 
may be designated as “dimorphic.” This distinction, howeve!, 
seems much more pronounced when the internal structure is com 
pared. The empty glumes of both spikelets possess the same struc 
ture, even if their form be distinct; but the flowering glumes and the 
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