THE STRUCTURE OF GRASSES 45 



The structure of grasses will be explained under the 

 following heads: root, rootstock, stem, leaf, flower. 



ROOTS AND ROOTSTOCKS 



The underground parts of grasses are popularly known 

 as roots but are of two kinds, differing in structure and 

 function, the true roots serving the purpose of taking up 

 water and food from the soil, the roots tocks serving for 

 propagation. 



Root. — The roots of grasses always tonsist of clusters 

 of slender fibers such as shown by wheat or oats when 

 pulled from the soil. 



The ends of the rootlets are covered with fine hairs 

 (root-hairs) giving them a velvety appearance. By 

 means of these the roots are able to absorb water from 

 the soil, and, dissolved in the water, the mineral sub- 

 stances present in the soil, these being the food of 

 the plant. Certain underground parts that are of- 

 ten confused with roots are described in the following 

 paragraph. 



Rootstock.— This is a modified stem which creeps 

 underground. It bears roots and small modified leaves 

 or scales, and sends up at intervals shoots which develop 

 into ordinary stems and leaves. The function of root- 

 stocks is to propagate or spread the plant. Rootstocks 

 are found in bluegrass, Johnson grass, Bermuda grass, 

 and others. Grasses with rootstocks are always peren- 

 nial. The part above ground may die but the rootstocks 

 remain alive over winter and send up shoots the following 

 spring. Rootstocks are also called rhizomes. 



