COBMS AND BOOTSTOCKS 361 



arise from the large terminal bud 1; and while 

 that stalk is growing, another terminal bud will 

 form beyond it to provide for the stalk of 1899. 

 We can also trace the history of the plant. The 

 position of the stalk of 1896 is marked by the 

 scar 3; that of 1895 by 4; that of 1894 by 5; 

 and that of 1893 by 6. Beyond that point the 

 parts have died away. There is, then, a progres- 



PlG. 379. 

 Rhizome of quack-grass. 



sive movement in this plant. Side branches have 

 started now and then, but they have not made 

 headway. 



453. Is this strong underground part of the 

 smilacina a root or stem ? It produces definite 

 buds, which roots do not ; and it also has nodes. 

 It is a subterranean stem, but roots arise from it. 



453a. This subterranean part Is a rhizome or rootstock, terms 

 which are applied to creeping underground stems, as distinguished 

 from roots. ' Some rhizomes bear rudimentary leaves, as that of the 

 quack-grass (Fig. 379), upon which the fibrous leaf-sheaths are promi- 

 nent. Many rhizomes bear scales at the nodes. Each joint of the 

 rhizome of quack-grass or Canada thistle may grow when broken 

 apart, as the farmer knows to hi.s sorrow. 



