ECADS. 



115 



From the above, as well as from figures 53 and 54, it may readily be seen 

 that AUionia linearis is a rather stable species as to root system, the root habit 

 differing only slightly in the two habitats. The clusters of small branches 

 were quite pronounced in the plains ecad, while this was compensated for in 

 the sandhill form by a somewhat greater degree of branching. The habit of 

 sending off one or more large and rather horizontal branches in the surface 

 foot of soil was characteristic in both habitats, as was also the strong tap- 

 root, which showed about the same degree of penetration in both groups. 



Fig. 53. — AUionia linearis from the 

 plains. 



Fig. 54. — AUionia linearis from the 

 sandhills. 



Abronia fragrans. — This plant is rather widely distributed over the plains 

 in disturbed areas, where, as in the sandhills, it frequently forms socies. The 

 large, showy, hemispherical clusters of flowers make it very conspicuous. 



