Nortu Haven Sanp PLaIns 591 
Bromus TECTORUM. — Epidermal layers of the two surfaces are 
very similar, the cells being perhaps slightly larger below, of me- 
dium size and colorless. Some of them are extended into long, 
unbranched, unicellular hairs, which are slightly longer on the 
upper than on the lower surface. The small mestome bundles 
are not enclosed in sheaths as in Cenchrus and Spartina. The 
larger bundles have parenchyma sheaths, but the cells are small. 
Subepidermal strands of stereome are found in the leaf-margins 
and above and below the larger mestome bundles including the 
bundle of the keel. Mesophyl is rather compact and occupies 
the entire space between the epidermal layers not taken by the 
bundles. Stomata are found on both surfaces of the leaf. 
SPARTINA CYNOSUROIDES. — Upper surface of the leaf much 
furrowed. Epidermis composed of small cells with rather thick 
walls curiously thickened or elongated on the outside, forming 
papillae or short hairs mostly with truncate or blunt points. At 
the bottom of each furrow are three rows of large colorless cells 
for storing water.* The stomata are situated on either side of this 
row of cells near the bottom of the furrow. Lower epidermis con- 
sists of small cells with very thick walls on the outside, nearly 
smooth. Subepidermal strands of stereome-cells occur above 
and below each mestome bundle, and each of the larger bundles 
is provided with a stereome sheath inside the sheath of green paren- 
chyma which encloses all mestome bundles. The stereome sheath 
is entirely wanting in some of the smal] mestome bundles and is 
partially developed in others. There is no distinct keel, but the 
median mestome bundle is slightly larger than the others and has 
larger strands of stereome above and below it. The stereome 
sheath is also well developed, but the cells of the parenchyma 
sheath are rather small. A layer of thick-walled cells separates 
the leptome and hadrome. 
CYPERUS FILICULMIS. — Leaf is conduplicate on drying. Very 
large colorless water-cells occur on superior surface : those in the 
center directly over the midrib are largest and all have rather 
thick outer walls with very thin partition walls between the cells. 
The sections studied had eleven mestome bundles, five on either 
side of the midrib. A subepidermal strand of stereome occurs 
* O’Brien, 2 c. 
