282 THE NURSERY LIST. 



sown as early as possible in spring ; or in the south they 

 may be sown in the fall. 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 cli- 

 mates, 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 soon crowd each other, and growth is checked, 

 causing them to ripen prematurely. Good sets should 

 not be more than a-half inch in diameter. Very small 

 onions which are selected from the general crop — called 

 " rare-ripes " — are sometimes used as sets, but they are 

 usually too large to give good results. Some onions — the 

 "multiplier" or "potato onions" — increase theinselves 

 by division of the bulb. The small bulb, which is planted 

 in the spring, splits up into several distinct portions, each 

 one of which will multiply itself in the same manner when 

 planted the following year. 



Onobrychis (Saintfoin). Lcguinitiosa:. 



Seeds, sown in spring where the plants are to remain. 

 Onosma (Golden Drop). Borraginacccr. 



Seeds, sown in the open in spring. Perennial species 

 by cuttings in summer. 



Opuntia (Prickly Pear, Indian Fig). Cadacea:. 



Seeds grow readily, sown as soon as ripe in ordinary 

 sandy soil, either in the house or outdoors. The joints 

 grow readily if laid on sand. It is customary to allow 

 these cuttings to dry several days before planting them. 

 See also Cactus. 



Orach [Atriplex hortcnsis). ChenopodiacccF. 

 Seeds, sown where the plants are to stand. 



Orange {Citrus Aunuitiuin, etc.). Riitacco'. 



Orange stocks are grown from seeds, which should be 

 cleaned and stratified in sand or other material, until sow- 

 ing time. The seeds should not be allowed to become 

 hard and dry. Some prefer to let the seeds sprout in the 

 sand and then sow them in the nursery, but they must be 

 carefully handled. The seeds are usually sown in seed 

 beds, after the manner of apple seeds, and the seedlings 

 are transplanted the next fall or spring into nursery rows. 

 Care must always be exercised in handling orange plant/* 



