76 BOTANY OF CROP PLANTS 



worst weeds, owe their obnoxious character mainly to the 

 possession of rootstocks. Such plants are not dependent 

 upon seed production alone, but in addition spread by means 

 of their rootstocks. The rootstock is a storehouse of food 

 material, and although the leaves and stems above ground 

 may be destroyed, new shoots are sent up from it, drawing 

 upon the stored food supply. For this reason, perennial 

 weeds of all kinds are difficult to eradicate. Any method of 

 elimination adopted is based upon the knowledge that the 

 food stored in the underground stems is made in the green 

 leaves; therefore, the development of green leaves must not 

 be allowed. 



Rhizomes of grasses bear brown or colorless sheathing 

 scales (rudimentary leaves) containing in their axils active 

 buds which may develop into erect stems. Under favorable 

 conditions, roots are produced at the nodes of the rhizomes. 

 Grasses possessing rhizonies are rhizomatous. 



When the intemodes of the rhizomes are very short, the 

 culms are close together, and the grass is known as a tufted 

 grass or as bunch grass, as in meadow fescue {Festuca pra- 

 tensis) . Many of our most valued range grasses have the 

 bunch habit. When the internodes are long, the culms are 

 more widely separated, and a creeping grass, as awnless 

 brome grass (Bromus inermis), is the result. 



Stoloniferous Grasses. — When the horizontal stems are at 

 or above the surface of the ground, they are called runners or 

 stolons, as in buffalo grass {Buchloe dactyloides) . Outside of 

 the grass family, the runners or stolons of strawberry are 

 very typical. Stolons are about as effective as rhizomes in 

 propagation. They usually produce a more open, loose tuft. 

 This is due to the long internodes. Stoloniferous grasses do 

 not produce as solid and uniform a turf as most rhizomatous 

 grasses. Neither is it likely that the former would produce a 



