MICHIGAN ACADEMY OF SCIENCE. 



341 



PINUS STROBUS NO. III. 



PINUS STROBUS NO. IV. 



The average tap root curve would lead to the expectation, within a 

 reasonable range, of the following tap root lengths, in Pinus strobus at 

 10-day intervals during the major part of a normal growing season in the 

 M. A. C. Forest Nursery. 



I. 



June 28 3.5 



July 8 3.8 



July 18 4.2 



July 28 4.6 



Au^st 7 4.9 



August 17 5.3 



August 27 5.7 



September 6 6.0 



September 16 6.4 



September 26 6.8 



cm. 



cm. 



