1906] TRANSEAU—BOGS OF THE HURON RIVER VALLEY 19 
of midvein, one or two cell layers on the side of the hadrome, develop- 
ment of the stereome cells also smaller on hadrome side; palisade 
of two cell layers; lower epidermis covered with wax, especially at 
* the stomata, guard cells slightly elevated. Mycorhiza present in the 
larger roots, wanting in the hairlike branches, no root hairs. - 
Andromeda polijolia—Leaf: margins revolute, upper epidermal 
cells thick-walled, radial walls undulate, no stomata; lower epidermis 
supplied with unicellular short stiff hairs, and covered with wax, 
stomata slightly protuberant, strongly cuticularized beneath mid- 
vein; palisade of three layers of long narrow cells; stereome strongly 
developed above and below vascular bundle; on the ventral side 
this adjoining three layers of large thin-walled air cells and a one- | 
layered hypoderma. Root: resinous deposits throughout, no mycor- 
hizal fungi found. 
Chamaedaphne calyculata.—Leaj: margin slightly revolute, epi- 
dermis thick-walled, heavily cuticularized, cuticle rough, no stomata 
on upper surface; ventral epidermis covered by shield-shaped multi- 
cellular hairs, and a deposit of wax; cuticle unusually thickened 
beneath the midvein, guard cells sunken, subsidiary cells protuberantr 
palisade tissue of four or five layers. Root: inner and radial walls 
thickened, cortical tissues thick-walled; resin deposits in vascular 
bundle and cortex; no mycorhizal fungi found. 
Chiogenes hispidula—Lea}: margin revolute, epidermal walls 
very thick, cuticle present, papillate, palisade not strongly developed; 
mesophyll cells in part thick-walled and in part thin-walled; resinous 
bodies in the epidermis; stomata slightly protuberant. Stem: resin 
Present in cortex; mycorhizal fungi in the epidermis of the smalle; 
Toots and throughout the cortex of the larger. 
Vaccinium corymbosum.—Leaj: cuticle present, epidermal walls 
hot thickened, palisade of one layer, mesophyll tissues with resinous 
bodies, cuticle of ventral surface papillate; abundant unicellular 
irs on lower epidermis few on upper; leptome side of mid-vein 
adjoined by three layers of stereome and two or three layers of hypo- 
dermal collenchyma,.on the hadrome side reduced to two of stereome 
and two of collenchyma, cuticular papilli usually developed beneath 
the midvein and at edge of leaf. Root: cortical tissue with resin, 
mycorhiza present. No resin deposits found in stem. 
