THE NURSERY-LIST 369 



if kept warm and moist, will grow. The olive is often propagated by 

 truncheons of trunks. A trunk 2 or 3 inches in diameter is cut into 

 foot or two-feet lengths, and each length is split through the middle. 

 Each half is planted horizontally, bark up, 4 or 5 inches deep, in 

 warm moist soil. The sprouts which arise may be allowed to grow, 

 or they may be made into green cuttings. Knaurs (see page 107) 

 are sometimes used. The olive can be budded or grafted in a variety 

 of ways. Twig-budding or prong-budding and plate- or H-budding 

 (Figs. 146, 147, 149) give admirable results, and are probably the 

 best methods. Twig-budding is the insertion of a small growing 

 twig which is cut from the branch in just the way in which shield- 

 buds are cut. (Fig. 146.) Side-grafting is also successful. (Fig. 187.) 

 In California, owing to the uncertainty of getting a good stand 

 of cuttings of green wood and the slowness of rooting cuttings 

 of large wood, the practice of raising olive seedlings and budding 

 on them has become more popular. After the pulp is removed, the 

 extreme point of the pit or stone is cut off with ordinary pruning 

 shears, when the seed germinates very readily. This method insures 

 a good stand without injury to the kernel. Ordinary shield-budding 

 may be performed any time in the year when dormant buds may be 

 obtained and the seedling is in condition to receive them. The root 

 system is better under this method of propagation. 



Omphalodes. Boraginacece. 



Handled by seeds, division of the plant and of the runners of some 

 species. 



Oncidium. Orchidaceop. 



Propagated by division or notching the rhizome between the 

 pseudobulbs just before the growing season. In some species 

 detachable buds are produced in the inflorescence, and these give 

 young plants. See Orchids, page 372. 



Onion (Allium Cepa and A. fistulosum), Liliacece. 



Onions are mostly grown from seeds, which must be sown as early 

 as possible in spring ; or in the South they may be sown in autumn. 



They are also grown from " tops," which are bulblets borne in 

 the flower-cluster. These are planted in the spring, or in the fall in 

 mild climates, and they soon grow into large bulbs. 



" Sets" are also used. These are very small onions, and when 

 planted they simply complete their growth into large bulbs. Sets 

 are procured by sowing seeds very thickly in poor soil. The bulbs 

 2s 



