372 BOTANICAL GAZETTE [JUNE 
tension plant, and N the control. The areas given are those meas- 
ured on the drawings. 
TABLE III (AREA METHOD) 
Plant me of whole section | Area of xylem and pith Area of xylem Percentages 
No. 2A. T aay ae ee. pa 53 
No. 2A. N. 97 .62 34.32 10.00 
Wo. 3 Fr. 153-49 60.64 20.13 82 
No. 3 N. 154-20 61.62 FL .O3 
INOSABu 4. 129-49 53275 14.65 ee 
No. 2B. N. 125.10 ONT 15.03 
The last plant (no. 2B. T) is one of three mentioned above. This 
shows a slight difference in favor of the normal and by so much 
weakens the general conclusion. 
The first four plants of the preceding table were used to test the 
differences by the weighting method. The two methods show results 
which are very close, only varying by 2 per cent. to 4 per cent. 
TABLE IV (WEIGHT METHOD) 
Weight of drawing of 4 E Percentages 
ae  crost-eection-~ Weight of xylem Difference 
No. 2 T. 1 .878™ o.238™ 49 
No. 2 N. 1.89 6.19 
is (oP a Be 2.8641 0.382 78 
No. 3 N. 2.9301 G.275 
Brassica oleracea (greenhouse cultures) 
Five plants of Brassica oleracea were put under tension in a similar 
way as explained for Helianthus annuus. The seeds were planted in 
20°™ pots and placed in the greenhouse. In a little more than a 
month these had grown sufficiently for experimentation, being about 
7° tall. The original weight for each plant was 50%"; this was 
gradually increased until the final weight reached 1000%. The 
duration of the experiment was two weeks. 
Sections were made freehand at places 5°™ and 1°™ above the 
ground in both control and tension plants. An examination of the 
various anatomical structures failed to show any constant differences 
between the control and experimental plants. The xylem ring in the 
