


1901] GEOTROPISM OF STEMS 421 
as occurs in roots when the experiment lasts more than a 






few hours. 
| 
| January 16 | January 17, 9 p.m, 
| Length | Growth | ges piensa Curve 
I yym™m 3mm 3 | 4 go° 
2 12 7 3-4 3 75 
3 6 4 2 3 90 
4 II 7 2-3 3-4 80 
5 14 z 3 3-4 go 
6 14 6 3 4 go 
7 19 E) 3 4 95 
8 7 5 2 3 70 
9 2+ 3 2 a+ 50 
10 15 5 3 4 70 
It 9 ‘i 2-3 4 990 
12 9 I I 2-3 tea 
13 5 3 4 a2 go 
4 4 3 2 3 85 
15 10 6 3 4 bezier => 


The root of Yucca begins to grow earlier than that of Phoenix, 
and a considerable part of the growth of the cotyledon takes 
place afterward in the development of the elbow from whose 
‘inside the plumule breaks, as shown in fig. 3. Yucca is more 
like Allium than is Phoenix, but in neither does the cotyledon 
develop visible chlorophyll. Experiments with a considerable 
number of Yucca plants were perfectly harmonious during the 
first growth, and it will suffice to report on three typical plants. 
The first two seedlings were marked and placed horizontal 
November 9, 5:00 P.M. 
I.. Lengtho™", of whichrootis4.5™™. November 10, 11:00 A.M.: growth 
in zones 1-3, 2.5", mostly in zone 2; curve 85° in zone 2; in zone 6-9 growth 
0.8™™ without curve. November 12,11 :00A.M.: growth in zones 6-9 is 1.4™™, 
still straight. 
2. Length 5 ™, of which root is 2™™. November Io, II :00 A.M.: no appre- 
ciable change. November 11, 12:00 A.M.: growth in zone 1, 0.4™™; curve 
15°; trace of growth throughout; growth above zone 5, 2.0™™ without curve. 
November 12, 11:00 A.M.: growth'r ™™ in zones I-3 ; curve 40° ; growth above 
5, 2.8™™, still straight. 
3. Began November 22, 9:00 A.M. Length 3™", of which root is 1™™. 
