PHENOMENA OF PLANT-LIFE. 



Flow of Sap Concluded. 



69 



TABLE 



Showing the variations in Water Gauges attached to roots of trees. 

 The figures indicate inches of water in tubes of such size that a column 

 of thirty-six inches weighs one ounce. The minus sign denotes absorp- 

 tion of the water by the root, and the absence of the sign denotes flow of 

 sap from the root. The size of the trees is unimportant, but they were 

 all vigorous specimens, standing in open ground. A summary of the 

 principal facts relating to the four species which showed the greatest 

 fluctuations is given below. 



Acer saccharinum. Water gauge attached, May 1. Maximum absorption was 69 

 inches or 1.91 ounces of water, May 10. Minimum, 2 inches or 0.055 of an ounce, 

 June 1. Total absorption, in the month of May, 410.7 inches or 11.4 ounces. No 

 flow of sap. 



Quercus alba. Gauge, attached, April 11. Maximum absorption, 46 inches or 1.28 

 ounces, May 2. The tube, however, was often emptied of its contents within an hour 

 or two after it was filled. Maximum flow, 2.5 inches or 0.07 of an ounce, May 26. 

 Total absorption, 759.1 inches or 21.09 ounces. Total flow, 3.5 inches or 0.097 of an 

 ounce. 



Ulmus Americana. Gauge attached, April 11. Maximum absorption, 26.5 inches 

 or 0.74 of an ounce, April 15. Maximum flow, 12.5 inches or 0.34 of an ounce, April 

 29. Total absorption, 155 inches or 4.30 ounces. Total flow, 256.8 inches or 7.13 

 ounces. 



Pyrus Mahis. Gauge attached, April 11. Maximum absorption, 25.0 inches or 0.70 

 of an ounce, April 16. Maximum flow, 22 inches or 0.60 of an ounce, May 16. Total 

 absorption, 175.3 inches or 4.85 ounces. Total flow, 290.7 inches or 8.07 ounces. 

 10 



