THE RHEOTROPISM OF ROOTS 351 
If this evidence is reliable, it shows that the rheotropic 
‘stimulus is received and transmitted by a part of the root 10™™ — 
moved from the limit of the elongating zone, and 12™" from 
the part which first curves. Remarkable as this result may 
seem, | believe it will stand the test of time. One must master 
certain amount of technique to obtain success; but the tech- 
migue once learned, the preparation is easy and the results sure. 
C. RESULTS WITH OLDER PLANTS. 
I, WITH SECONDARY ROOTS. 
It cannot be inferred a priort that the secondary roots of 
fon-sensitive primary ones would be found non-sensitive, nor 
can it be inferred that the secondary roots of sensitive primary 
. be found sensitive. It seems to be true, however, 
“at secondary roots are sensitive or insensitive according to — 
Seisitiveness or insensitiveness of the primary root. Berg” — 
found both primary and secondary roots positively rheotropic bes 
a mays, Fagopyrum tataricum, Tropaeolum majus, Lupinus albus, 
hg Vicia faba, V. sativa, and Helianthus carina while 
» Stew well and grew straight. © a 
” Majus was tested in the same way ’ but i in ee 
aging from 150 to 600™ per minute. Only ten sec : 
ae Present, and AE the test Tasted 
Toots grew straight. : 
ty Rheotropismus. Lunds Universitets Assit. Pa 
