ROOT GROWTH AND DEVELOPMENT 
221 
I S'C 20° 25^ 30° 35" 40° 45 ^ 
Fig. 5. Average hourly rate of growth of the roots of Prosopis velutina ( ), 
and Fouguierialsplendens ( ) at the temperatures given (X ca. 100). 
Species grew at a more rapid rate than the roots of the other species. 
These points were subsequently verified in more precise cultures, as, 
also, they verify the previous observations already referred to. 
