ROOT SYSTEMS OF MIXED-PRAIRIE SPECIES. 



63 



color. The roots usually run off obliquely to distances varying from 0.5 to 

 1.5 feet horizontally from the base of the clump before turning abruptly down- 

 ward (fig. 26). From here their course is in general vertically downward, 



Fig. 26. — Root system of Penlstemon ambiguus. 



