CHAPTER XIX 



TUBEBS — STABCH 



' rriHERE are buds that, though called to an inde- 

 X pendent existence, do not, before separating 

 from the mother plant, store up provisions nor 

 thicken their scales; but the plant itself is charged 

 with feeding them. When it is intended that the 

 stem or branch shall itself maintain the buds it 

 bears, then, instead of coming out into the open air 

 where it would speedily cover itself with foliage 

 and flowers, it remains underground and has for 

 leaves only rudimentary scales. It grows so cor- 

 pulent and deformed as to cease to bear the name 

 of branch and to take instead that of tuber. As 

 soon as necessary supplies have been stored up, the 

 tuber detaches itself from the mother plant, and 

 thenceforth the buds it bears find in it abundant 

 nourishment for their separate existence. A tuber, 

 then, is an underground branch swollen with nutri- 

 tive material and having undeveloped scales in place 

 of leaves, and it is also dotted here and there with 

 buds which it must feed. 



"Let us now look at a potato. What do we see 

 on the surface ? Certain small cavities or eyes ; that 

 is to say, so many buds, for these eyes develop into 



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