58 
AMERICAN JOURNAL OF BOTANY 
[Vol. 8 
sider the state of activity of the cranberries and of the insect larvae, and, 
if possible, to adjust the length of the flooding period so that the larvae 
would be killed without injury, or at least without extensive injury, to the 
vines. A careful study of these problems is highly desirable. 
Summary 
In a study of flooding water of cranberry bogs of Massachusetts and 
Wisconsin a variation in oxygen and carbon dioxide content of the water 
was observed. 
The effect of cloudiness on the oxygen and carbon dioxide content of 
water is indirect, resulting from the action of light on submerged vegetation. 
The variation in oxygen and carbon dioxide content of flooding water 
in the cranberry region of Cape Cod, Massachusetts, as affected by light 
intensity, organic matter, and abundance of vegetation, is show^n. 
An experiment is described showing the effect of shading submerged 
cranberry vines. The resulting injury is due to reduction of oxygen 
content of the water. No essential difference was observed between the 
amount of injury to shaded vines in pond water and that to shaded vines 
in bog ditch water. 
The flowers and growing tips of shoots, which were the parts most 
seriously affected, have a higher respiratory rate than old shoots, as shown 
by experimental results. This accounts for their greater injury by sub- 
mergence in water deficient in oxygen. 
Injury is most apt to occur to a bog by flooding during cloudy weather. 
Bureau of Plant Industry, 
Washington, D. C. 
LITERATURE CITED 
1. Birge, E. A., and Juday, C. The inland lakes of Wisconsin. The dissolved gases of 
the water and their biological significance. Wis. Geol. and Nat. Hist. Survey 
Bull. 22. 1911. 
2. Brown, W. H., and Heise, G. W. The relation between light intensity and carbon 
dioxide assimilation. Philip. Jour. Sci. 12: 85-95. IQI?- 
3. Maige, G. On the respiration of different floral organs. Ann. Sci. Nat. Bot. IX. 
14: I (not seen). Abstr. in Exp. Sta. Rec. 25: 729. 1911. 
4. Nicolas, G. The variation in the respiration of plants in proportion to age. Bull. 
Soc. Nat. Hist. Afrique Nord 1910: 109 (not seen). Abstr. in Exp. Sta. Rec. 26: 
628. 1912. 
5. Pettersson, O., and Sonden, K. Uber das Absorptionsvermogen des Wassers fiir die 
atmospharischen Gase. Ber. Deutsch, Chem. Ges. 22: 1439. 1889. 
6. Roscoe and Lunt. Chem. Soc. Journ. 55: 552. 1889. 
7. Winkler, L. W. Die Bestimmung des im Wasser gelosten Sauerstoffes. Ber. Deutsch. 
Chem. Ges. 21: 2843. 1888. 
