H(nv THE PLANT I-IVES I'J I 



tlio plant is cniiiposod,— now cells are made, and 

 others are niodilifd in size or form. It is |Mf>K- 

 ably imi)(»ssii»l»' t"nr a plant to live without j^i-ow- 

 iui::; hut under jfoor conditions the growth may he 

 so slii^ht tiiat the plant is no longer of any use 

 to the farmer. 



20.'). The younii: stcMiis of many j>lants elongate 

 throughout the «-nlire length of the growing 

 part. I^ut the lower part soon i-eaehes the limit 

 of its growth, the rear internode — oi- s))ae(' hc- 

 tween the j(^ints — ceases to elongate, ami fiiithei- 

 growth in length jiroeeeds only in the newei- jiails 

 al>ove. That is, while there is an elongation or 

 stretching of the shoot itself, this elongation 

 gradually Ics.sens below, so that the region of 

 most rapid growth is constantly in the freslu'st 

 and softest part of the shoot. Notice that the 

 distance between the joints in growing slioots 

 tends for a time to increase. 



'2^Wy. The root grows differently. The tip of 

 the gr<^wing root is hai'd, being protected by what 

 is known as a root-caj>. (trowth in lenirth takev 

 place jnst beliind this hard tip, not tlir<Mighout 

 the lenirth of the growitig part. The root, tliere- 

 fore, is able t(^ ]>ush its way around obstacles. 



'J()7. In most of our woody i>lants, increase in 

 diameter is effected by a layer of growing tissue, 

 the cambium, located just beneath the bark; and 

 every vear it gives rise to a new layer of wo(»d on 



