OLEA — ONION. 281 



Olsa. Oleacece. 



The ornamental species are grown from cuttings of 

 ripened shoots, either under frames or in the border, and 

 also by seeds. For propagation of O. Europica, see Olive 



Oleander. See Nerium. 



Oleaster. See Ek'eagniis. 



Olive (Olea Europa;a). Oleacea;. 



Tlie olive is grown in large quantities from seed, espe- 

 cially in Europe. The pulp is removed by maceration or 

 by treating with potash. The pits should be cracked or 

 else softened by soaking in strong lye, otherwise they will 

 lie dormant for one or two years. Cuttings of any kind 

 will grow. Limbs, either young or old, an inch or two 

 inches in diameter, and from i to 2 feet long, are often 

 stuck into the ground where the trees are to .grow, or they 

 are sometimes used in the nursery. Green cuttings, with 

 the leaves on, are often used, being handled in frames or 

 in bo.xes of sand. Chips from old trunks, 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 64) are 

 sometimes used. The olive can be budded or grafted in 

 a variety of ways. Twig-budding and plate or H-budding 

 {Figs. 96, 97. 98) give admirable results, and are probal)ly 

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

 small growing twig which is cut from the branch in just 

 the manner in which shield-buds are cut. (Fig. 96.) Side- 

 grafting is also successful. (Fig. 113.) 



Omphalodes, Picotia. Borraginacea: . 



Freely increased by means of seeds planted in spring, 

 or by division. 



Oncidium. OrcJiidacece . 



Division. In some species detachable buds are pro- 

 duced in the inflorescence, and these give young plants. 

 (See also under Orchids.) 



Onion {Allium Cepa and A. fistulostcm]. JAliaccce. 



Onions are mostly grown from seeds, which must be 



