i 

.” a 











Igor} GEOTROPISM OF STEMS 415 
Reve lencth |. .c h Zone most Cc Growing 
gt rowt cheved urve eaies 
I 20,7" 2.9™n 3-4 7 oe 
2 19. 1.5 5 70 
3 5. 1.8 4 go 
4 | 14 1.4 4 90 
5 24 1.8 4 60 
6 19 1.0 3-4 65 
ih 15 2.6 4 60 
8 22. 1.6 3-4 70 
9 | 14. 2.4 3-4 50 
Io 33- 3. 3-4 50 
Av | 18.52" | 2.0% 4 70° 5 




The subjects of the experiment whose result is next tabulated 
had been soaked twenty-four hours. The coats were removed 
and the “caulicle’” was marked off into 1™ zones, and the 
embryos were fastened horizontal. The first column gives the 
total length of the descending axis; of this the rudimentary root 
was I.g-2.5™™. Figures in italics are the zones of sharpest 
curvature. All zones of the hypocotyl grew in length, but the 
growth reached a minimum at some distance from the tip which 
I have construed as limiting the growing region of the “root.” 
The experiment began at 10:30 A. M., November Ig. At 4:00 
P.M., November 20, all seedlings were curved go”. 





4p. m. November 19 4p. m., November 20 
Length : 
Growth Curve - Growth sepia 
: Oe Coc = 20° 17mm 5 6(+) 
2 9 0.8 5 40 16 ¢ ‘ 
3 7 0.8 d 30 16 4 rs 
4 7 a2 3 20 16 5 5 
5 8 0.4 4-5 30 17 ee liis 
6 7 ? 2-3 10 II 4 4 
7 7 ? 3-4 10 14 5 5 
8 a ? 15 18 Z 4 
9 9 0.4 ¢ 15 15 4 4 
bdo) 8 0.5 40 15 4 4 
- 7 J 2-4 15 13 ba 
= 9 0.3 4-5 16 13 os | S 







