1921] EMERSON—BOG PLANTS 363 
Typha latifolia.—The rhizomes of this species assume about the 
Same depth in mineral or peat soil. Those measured varied 
from 15 to 30cm. deep in peat, and from 12 to 25 cm. deep in 
mineral soil. The roots extended diagonally or vertically down- 
ward. The deepest extended far below water in both types of 
soil. A few of the vertical roots were found exceeding 60 cm. in 
depth. On account of the turbid water they could not well be 
followed to a greater depth. 
Sagittaria latifolia.—This species is not very common in the bog, 
but is included because it also grows outside of the bog and affords 
opportunity for comparison in the two habitats. While there is 
~Lupaners variation in the depth of various parts of a given 
50 cm. ef L 
3:—Carex filiformis, map of rhizome system: A, aerial stems; L, living 
Breda to older rhizome; solid black line, living erect depth 8 cm. at aerial 
stems and going down to 30 cm. between aerial parts. 
thizome system, corresponding parts were found to assume about 
the same depth in various soils. The aerial parts arise from the 
thizome at about 4-6 cm. deep, while at other places the rhizome 
gradually descends to depths of ro cm. or more. The root behavior 
is almost identical with that of Typha latifolia. 
Scirpus validus—The rhizomes assumed a depth of 12-15 cm. 
in all soils where the species was found. A few of the roots 
extended downward to a depth of 30-40 cm. Nearly all of the roots 
were vertical, hence the entire subterranean system was below 
water. This bulrush was fairly common along the lakeward margin 
of the bog as well as in fens. 
Carex filiformis—This sedge was found in the bog only. Its 
roots and rhizomes varied in depth from 5 to 30cm. The roots 
were approximately horizontal (fig. 3). 
