CHAPTER II. 



SEPARATION AND DIVISION. 



I. SEPARATION. 



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 

 up of a short and rudimentary axis closely encased in trans- 

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

 ened parts are stored with nutriment which is used during 

 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 close-fitting layers 

 or plates, as in the onion. 



Bulbs often break up or divide themselves into two or 



ig. Bulb of Lilium can- 

 didum (xK). 



