CHAPTER 11. 



SEPARATION AND DIVISION. 



I. SEP.^RATION. 



Separation, or the multiplication of plants by means of 

 naturally detachable vegetative organs, is effected by means 

 of bulbs, bulbels, bulb-scales, bulblets, corms, tubers, and 

 sometimes by buds. 



Bulbs of all kinds are specialized buds. They are made 

 vip of a short and rudimentary a.xis closely encased in trans- 

 formed and thickened leaves or bulb-scales. These thick- 

 ened parts are stored with nutriment which is used durmg 

 subsequent growth. Bulbs occur only in plants which are 

 accustomed to a long period of inactivity. Many bulbous 

 plants are peculiar to dry and arid 

 regions, where growth is impossible 

 during long intervals. A bulb is, 

 therefore, a more or less permanent 

 and compact leaf-bud, usually occu- 

 pying the base of the stem under 

 ground and emitting roots from its 

 lower portion. Bulbs are conveni- 

 ently divided into two great classes 

 — the scaly, or those composed of 

 narrow and mostly loose scales, as 

 in the lily, and laminate or tunicate, 

 or those composed of more or less 

 continuous and cluse-fitting layers 

 or plates, as in the onion. 



Bulbs often break up or divide themselves into two or 



(26) 



ig. Bulb of Lilium can- 

 didum [yLYi). 



