86 



PLANT LIFE. 



tinguished from the root by not forming through segmenta- 

 tion from the outer faces of the initial cell or cells a many- 

 layered ejudermal cap. In further contrast with the root, 

 which often has no true ejjidermis except the root-cap, the 

 shoot is characterized by possessing an uninterrupted epider- 

 mis over its entire surface, consisting always at first of a 

 single layer of cells. This epidermis persists as a surface 

 covering either throughout the life of the shoot, or for a long 

 [jeriod, being replaced only upon the 

 older surfaces of the axis by subsetjuently 

 formed protective layers. (See* i34-) 

 103. Branching. — I]ranches of the 

 shoot arise from lateral buds, which are in 

 all respects similar to the terminal buds 

 just described. If for any reason, the 

 terminal bud of the stem becomes de- 

 stroyed, or its growth arrested, a branch, 

 developing from a lateral Ijud near by, 

 ma)' assume the position and habit of 

 the main axis, its own normal mode of 

 development being altered. In many 

 ]")lants the death or arrest of the ter- 

 minal bud recurs at regular intervals. 

 In such plants, thereCore, the main axis 

 is really a succession of lateral branches, 

 KiG .,7.— Shout oi Kuro- and the bran< hing is said to be svmpo- 



pean hndeu. i", the last j- 1 ir > ^ , 



internode formed by the """ (^0- 97)- ^^ SOme plants, e.g., 



bud of present season i-l * 1 , ill j. i ■ 1 



This dies and drops off '''ac, two lateral Ijuds standing at the 



and the shoot will he ,1 , , ■ ,- 1 , ■ , 



formed next year by the samclcvel may devcloj), it the terminal 



last axillary bud, d, r -i r 1 ■ 1 1 



which appears to be One lails. lu tills Case the slioot sceiiis 



terminal after loss of /. . 1 ■ ■ , ■ ^ ^ , , , r,,, . 



Half natural size. —After to divide luto twoei|ual branches. Ihis, 



however, is not true, but false, or sv)ii- 



poiJial, dichotiimv. True dichotomy, like tiue dichotonu' of 



the root, occurs onl)- m those plants in which the axis has 



