190 Principles of Plant Culture. 



354. The Corm (Fig. 92) differs from the bulb chiefly 

 in being without scales. The food is deposited in the 



thickened stem. The 

 corms of our flowering 

 plants, as the crocus, cyc- 

 lamen etc., are general- 

 ly called bulbs in com- 

 merce. 

 355. The Tuber.of which 



Fig. 91. Bulblets Fig. 92. Corm of the COmmon potato is the 



of "top" onion, «™«"^' j"''^ .^'7" most familiar example, 



sometimes used as conns (buds) for fol- -»- ' 



onion "sets." lowing year. differs from the corm iu 



being the end of an underground branch of the stem 

 (115), instead of developing in direct contact with the 

 parent. It also has more numerous buds (eyes) than the 

 corm. 



356. Propagation from Bulbs, BulbIets,Corms and Tubers 

 is a very simple oijeration and consists merely in plant- 

 ing these parts in the place where the plants are desired. 

 Tubers may be cut into pieces containing one or more 

 buds each, if desired. The rules gi\'en for planting seeds 

 (314:) apply equally well here. All should be stored for 

 preservation in a cool, moderately dry place, that is free 

 from frost. They retain their vitality but a single 

 year. 



In the methods of propagation thus far considered, 

 with the sole exception of layering (349),' advantage ha.s 

 been taken of a natural mode of plant multiplication. 

 The skill of the cultivator, however much it may assist 

 the processes, is not necessary t( > their success, since wild 

 plaints habitually increase by the same methods. We , 

 will now consider a method which is less often illustrated 



