﻿BRIEFER ARTICLES 



PHYSICAL CONDITIONS IN SPHAGNUM BOGS 

 The experimental data collected by Professor Henry J. Cox 1 

 of the United States Weather Bureau in regard to frost and tem- 

 perature conditions in cranberry marshes do not seem to have 

 received attention from reviewers of botanical literature, and their 

 bearing on the causes of the peculiar flora of sphagnum bogs seems 

 to have been overlooked. With a view to protecting the cranberry 

 crop in cultivated marshes by predicting frost and thus enabling 

 the growers to avoid danger to the crop by flooding the marshes, 

 he conducted a very thorough investigation of frost and temperature 

 conditions in the bogs of Wisconsin. He also secured some data 

 on bogs in Massachusetts, New Jersey, and Washington. The 

 following facts, which seem to have an important bearing on the 

 possible causes of the inhibition from sphagnum bogs of plants 

 other than bog xerophytes, have been summarized from his bulletin. 



A. AIR TEMPERATURES 



i. Comparison of bog with hard land.— The mean minimum 

 temperatures of the air at station 2 (in the bog over a dense growth 

 of saturated sphagnum) and at station 9 (over sandy loam in a 

 garden at the border of the bog, elevation of the surface of the soil 

 approximately 10 feet above the surface of the bog) for May, 

 June, July, August, September, and October 1907, at Mather, 

 Wisconsin, were as follows (table 18, p. 81): 



Wisconsin.' Bulletin T, U.S. Dept. A^ric, Weather Bureau, iqio. 



159] [Botanical Gazette, vol. 61 



