52 ROOT DEVELOPMENT IN THE GRASSLAND FORMATION. 



somewhat woody, which tapers very rapidly, so that at a depth of 8 inches it is 

 seldom over 2 mm. in diameter. Just below the ground-line it gives off large 

 numbers of rootlets usually running in a direction parallel with the soil surface, 

 and varying from threadlike to those with a diameter of 3 mm. Some were traced 

 at a depth of 0.2 to 0.3 foot to 3 feet from the base of the plant. As shown in 



Fig. 21. — Mentzelia nuda. 



