94 GENERAL BOTANY 



underground root-stocks, e.g. of grasses, and plants 

 of the Ginger and Canna kind, the horizontal stems 

 of many orchids, and the Vine. 



Examine a piece of Vine stem or of CISSUS. The 

 leaves are alternate and some of them, but not all, 

 have tendrils opposite to them. There are generally 

 two leaves with tendrils opposite them, then one with- 

 out, two again with tendrils and one without ; though 

 this is not invariably the arrangement. Those leaves 

 which have a tendril opposite them have no buds 

 in their axils, or if there be a bud it is very small and 

 has arisen as an extra one. 



If we apply the rule that branches arise only in 

 the axils of leaves, and that every leaf has its axil- 

 lary bud, it follows that the tendril is really the 

 continuation of the axis immediately below it, and 

 has been pushed to one side by the branch which 

 arises in the axil of the leaf opposite, and then grows 

 straight on as if it were a continuation of the original 

 axis. If there is a second leaf, that leaf has of course 

 its axillary bud. At the next node, the shoot again 

 becomes a tendril, and is in its turn pushed to one 

 side by an axillary branch. This is a typical sym- 

 podial arrangement. 



3. It often happens that a bud which, because 

 it is shaded or for some other reason, does not get 

 its due supply of sap and does not grow out into 

 a branch, yet remains alive, and may develop after 

 many years if stimulated to do so by the destruc- 

 tion of other branches. It grows slowly, so as to 

 remain at the surface of the axis as it increases in 

 thickness. 



