9 



ROOTS. 



Roots. Although popularly so considered, it is by no means 



the case that all parts of plants which grow beneath the surface 

 of the ground are roots. There are many stems beneath the 

 surface and many roots above. Roots have no leaves, and are 

 otherwise simpler than stems. They elongate by a rapid multi- 

 plication and growth of the cells a very short distance (perhaps 

 the one-sixteonth of an inch in case of Indian corn) back of the 

 extreme ti}* end. At such place, called "primary meristcm,'* 

 the cells rapidly increase by division, some of which continue to 

 remain small and keep on dividing. 



A portion of stem, on the other 

 hand, usually produces leaves, 

 buds, and when young elon- 

 gates by a multiplication and 

 growth of the cells for a con- 

 siderable portion cf its length. 

 The tender, grov.iug tip of a 

 root is protected as it pushes 

 along through the soil by a 

 root-cap consisting of some 

 older and harder cells. As 

 these cells wear ofE, others 

 crowd forward and take their 



FlQ.l.-Longitudinal section through the places. In graSSCS the grOWth 

 apex of a root of Indian i-orn, Imll of which i o o 



represents t ho oeilft as empty; a. o. outer and . .1 Tirimnrv rnnf i<j snmi 



older portion ot the root-cap; above this is 01 tue primary root IS SOOU 

 the younger portion, Just above which are , , , i t 



very small cells that divide and make new overtaken and IS Scarcely CllS- 

 cells for increasing the length of the root 



and replenishing the root-cap.-(Sach8.) tiuguishable from the Second- 

 aries or their branches. 



Roots perforate the leaf-sheaths or rudimentary leaves and 

 spring freely from the nodes or joints of underground stems of 

 June grass, quack grass, and in some instances they grow from 

 the nodes or joints of the stems above ground, especially where 

 they are moist and well shaded. All the seconda/y roots — branch 



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