18 BOTANICAL GAZETTE [JANUARY 
ecological attention, it is of interest to look at the anatomical char- 
acteristics of certain of these plants. 
Eriophorum virginicum may be taken as a type of this group, and 
also of the sedge zone vegetation in general. The culm is very 
slender and erect, leaves flat, and very narrow, perennial by root — 
stocks. Stem: epidermis very thick-walled and cuticularized. As 
development proceeds, certain radial rows of the primary cortex 
cells have their walls thickened, and served to connect the tissues of 
the central cylinder with those of the three-or four outer layers of 
hypodermal cells which also become thick-walled. Between these 
radial groups of cells lysigenic air cavities are formed. Root: epi- 
dermal cells in part thin-walled and in part secondarily thickened, 
no definite arrangement of the thick-walled cells apparent; internal 
structures closely resemble those of the stem; no mycorhiza present. 
Leaj: outer epidermal cell walls strongly thickened and cuticularized, 
radial and inner walls less so; lysigenic air spaces traverse the leaf 
longitudinally; a very thick layer of stereome adjoins the leptome, 
decreasing to one or two cell layers on the hadrome side of the 
bundle; chloroplasts massed among the outer layers of the cortex, but 
occur throughout. 
Sarracenia purpurea.—Well known for its insect-capturing 
pitchers. Stem: epidermis and first hypodermal layer thick-walled; 
lysigenic air cavities throughout pith and cortex; resin deposits 
confined to the epidermis and one or two hypodermal cell layers, but 
where wounded heayy deposits of resin take place in the exposed 
and underlying cells. Root: cell walls firm, resinous bodies present — 
throughout, but especially prominent in the two outer cortical layers, 
in which the cell walls are also strongly thickened. Leaj: epidermis 
thick-walled and, slightly cuticularized; stomata on both sides of 
the lamina, with guard cells strongly cuticularized and slightly 
protuberant; resinous deposits throughout; inner face of lamina 
with strong downward pointing bristles. 
Oxycoccus macrocarpus.—Stem: pith thick-walled, with resinous 
bodies; a thick layer of broad-celled bast forms a complete cylinder 
within the epidermis. Leaf: margins revolute, upper epidermis 
without stomata, heavily cuticularized, radial walls thick, wavy; 
hypodermal collenchyma of two or three cell layers on leptome side 
