370 BOTANICAL GAZETTE [JUNE 
TABLE I 
Plant Tension Normal (eee 
No. 1 A. 29.87% ster ait. 
No. 2 B. 42.45 AD Ft — 6 
No.3) B. 19.42 E? 29 8 
No. 4 B. 23 74 ea. 2 
No. 5 B. 35-62 54-52 50 
No. to B. 33.68 51.81 —= 54 
No. 9 A. 53-16 31.81 6 
Ne. 5 A. 56.13 36.45 54 
No. 8 A. 55-04 49 .42 II 
No. 1 B 34.65 32.65 6 
In the above table the second column contains the measurements 
of the relative area of xylem in the tension plant in section; the third 
column contains similar measurements in the control plants in section; 
and the fourth column contains percentage differences when the 
normal is taken as too. 
Ricinus communis (field cultures). 
The same experiments were made upon Ricinus stems, which were 
also cultivated in the open field during the summer months. Seven- 
teen, chosen at random, from the large number that were put under 
tension, showed after close observations the same general results as 
previously indicated for Helianthus. There is no constant increase 
in mechanical tissues as a result of a gradually increasing pull. The 
following table shows results of observations on ten plants. 
TABLE II 
Plant Tension Normal  oteeen i 
No. 1 A 24.20% «™.- nie 42 
No. 2A 59.615 39.87 5° 
No. 3A 26.45 23.915 II 
No. 5 A. 52.50 59-9 —14 
No. 9 A 52-39 56.555 — 
No. 10 A. Gh 00 55-7 — 24 
No. 3 B. 30.10 24.6 23 
No. 4 B. 35-30 33-9 4 
No. 5 B. 15.80 15-40 3 
No. 7 B. 50.30 48.70 > 
Nos. 1A, 2A, 3A, and 3B show results in favor of tension plants; 
nos. 5A and 10A show results in favor of normal plants; nos. 9A, 
