188 BOTANICAL GAZETTE 
experiment, and in others varied from 17° to 25°. 
ranged from 8 to 36 hours. Dolichos showed a very few roots 
inclined positively, and it is possibly rheotropic in a very | 
degree. 
3. Plants with a low degree of sensitiveness. 
It has already been intimated that the roots of the bulb: 
Allium cepa, and the primary roots of Dolichos lablab, may be 
slightly positively rheotropic. It is quite certain that the primary 
roots of the seedlings of Vicia faba, Lathyrus odoratus, Lupinus 
albus, and Tropaecolum majus are positively rheotropic, but otly 
in a comparatively low degree. Juel, in several tests with 
seedlings of the small-seeded variety of Vicia faba, had trouble 
in controlling the Sachs’s curvature. He obtained varyi 
responses and a considerable number of non- sexponsie ras 
He finally concluded that the roots were rheotropic, a 
_ More readily when so placed that the median plane of the set 
2 ling was parallel with the current rather than transverse. ‘ 
EEE 
. iiss were ‘iicesly of the viet’ known as Win 
a Apparently, however, this variety is less responsi 
_ used by Juel, since, as will be seen, the Windsor b 
Poe individuals as neutral, while it would be i 
ce ey current 100™ to 2500", seventeen grew pos : 
] negatively, and seventeen were neutral. In two experi 
_ each of which nine seedlings were suspended with the 
: dipping” into a brook of water in a wooded ravine wee 
the average temperature being about 23> all eig! 
_ femained vertical, though increasing in length !¢ 
in the period. In the one experiment the period wé 
| and the velocity 450™ per minute ; in the other, the 
: icers aa and the reel goo™ ae minu 
