CN ACD lal 
‘tgo2] THE RHEOTROPISM OF ROOTS 189 
In a variety of Vicza faba with seeds 1.5™ long and 1™ 
broad, perhaps the same used by Juel, twelve seedlings were 
placed under experiment with the revolving basin, water tem- 
perature 21°, velocity 300™ to 750™ per minute, and period 24 
hours. Six roots then showed positive curves from 15° to 90°, 
and the other six were vertical. 
As to the relative degree of response shown by the seedlings 
when the median plane is parallel to the current of water and 
when the median plane is transverse, my results, and probably 
those of Juel, are too few to account as of great importance. 
In one €xperiment with six seedlings, with the median plane 
transverse to the current, four roots out of six responded posi- 
tively, the greatest angle being 30°. In another experiment 
with _ seedlings, the median plane being parallel to the cur- 
: ent roots bent positively, two of them reaching an angle 
a In a third experiment with twelve roots, out of nine 
seep median plane parallel, four bent positively, while out 
oe ree with the median plane transverse, two bent positively. 
we shown that the root will respond to the water meeting 
ey: a4 Part of its circumference. 3 
: Ms low grade of responsiveness of Vicia faba to a current of 
rn not only in the fact of approximately 50 per 
© foots remaining neutral, but also in the exceedingly 
Pisoted latent period, and in the small angle attained in most 
tl ai - in the experiment with the twelve seedlings of 
‘Toots ag Vi tcta faba with a water temperature of 21°, no 
Positive ee : ee first 5 hours. In 8 hours four had curved 2 
oo ‘tours five had curved, and within the following _ 
on€ More curved. Of the twenty-three positively curved 
both Varieties of Vicia faba, only three attained angles ae - 
#89 > degrees from the vertical. The majority of 
odoratus and Lupinus albus are, at least in some varie- oe 
wey theotropic. The latter was found rheotropic by 
| these Species produce fairly straight-roots when 
— ‘With water temperature from 21° to 24° 
