1897] THE CURVATURE OF ROOTS 347 
Some are thrown from a position parallel to the longitudinal axis 
of the root and the end walls exhibited foldings, shallow and V 
_ shaped, but in no place do these elements exhibit the contours 
to be seen in curvatures of go° produced by geotropic excitation, 
where the radial and longitudinal axes were often equal. The 
epidermal cells of the convex side were torn and collapsed in 
places. The longitudinal walls of all cells on this side were 
thrown outward and inward from their natural positions. The 
end walls were sharply and deeply folded and pouched. 
The greater distortion of the cross walls on both sides of the 
organ is to be attributed in part to the fact that these membranes 
are quite newly formed and have not acquired a rigidity which 
enables them to withstand columnar strains of any amount. 
With the growth of the cortex of the concave side in thickness, 
the foldings in these walls are taken up in part or almost wholly 
in slight curvatures. 
TABLE X. 
Median longitudinal section of root of Zea mais geotropically excited for 
one hour, and then mechanically in the plane of would be curvature through 
go". 
MEASUREMENTS OF LENGTH OF CELLS OF CONVEX SIDE. 
Apical Basal Average 
(2p) 4 40: 4g 8 35 40° 4G: SR ARGS 
(2) 75 42 40 20 30 80 120 50.9 
(y. 45 40 40.4 50° ~ 50 80 50 80 54-4 
Wo 9R ee fe ga ee gg ee eS 
40 
59 
Se ae oo ee ae ee oe eee eR ag 
(7) 42 32 36 30 35 45 40 40 «(375 
(ae 9 gh, 0 3 
Average length of cells, - - - - - 44-63 
MEASUREMENTS OF LENGTH OF CELLS OF CONCAVE SIDE. 
Apical. Basal Average 
(Ep) 14 25 14 20 20 80 25 Ge 4 F7-Sh 
a ae ey ge ae a eee 
18 
