STRUCTURAL BOTANY. 



[86, 87. 



259. The principle of budding. Each leaf-bud 

 may be regarded as a dis- 

 tinct individual, capable 



of vegetating either in its 

 native position, or when 

 removed to another, as is 

 extensively practiced in 

 the important operation 

 of budding. 



260. Bulblets. In the Tiger-lily, 

 also in Cicuta bulbif era, and Aspidium 

 bulbiferum, the axillary buds sponta- m 290, showing the process 



of "budding."' 



neously detach themselves, fall to the 



ground, and become new plants. These remarkable 



little bodies are called bulblets. 



x 



CHAPTER XIX. 



PHYLLOTAXY, OR LEAF-ARRANGEMENT. 



261. As the position of the leaf upon the stem 

 marks the position of the axillary bud, it follows that 

 the order of the leaf-arrangement will be the order of 

 the branches also. Phyllotaxis, or leaf-arrangement 

 (from 0i5AAov, leaf, rdfa, order), depends chiefly on the 

 mode of origin of the leaves at the apex of growth, 

 and on the subsequent elongation and twisting of the 

 axis on which they grow. 



262. In regard to position, leaves are radical when 

 they grow out of the stem at or beneath the surface 

 of the ground, so as to appear to grow from the roots ; 

 cauline, when they grow from the stem ; and ramal 



