368 THE NURSERY-MANUAL 



Seeds should not be kept too long out of water. Also propagated by 

 dividing the rhizomes, and by tubers. 



Nymphoides, Limnanthemum (Floating-Heart). GentianaceoB. 



Increased by division of the plants. 

 Nyssa (Pepperidge. Sour Gum. Tupelo). Nyssacecz. 



Seeds should be sown as soon as ripe or else stratified; they 

 usually lie dormant the first year. Layers are sometimes employed, 

 but rooting is slow. 



Oak : Quercus. 



Ochna. Ochnaceae. 



In summer or autumn, cuttings may be made of firm or half- 

 ripened shoots. 



Ocimum : Basil. 

 Odontoglossum. Orchidacece. 



Propagation by division and by seeds. See Orchids, page 372. 

 (Enothera (Evening Primrose. Sundrop). Onagmceoe. 



Grown readily from seeds, some species blooming the first year 

 and others not till the second. Perennial kinds may be divided. 



Okra, Gumbo (Hibiscus esculentus). Malvaceae. 



Raised from seeds, sown where the plants are to stand, or often 

 started in pots in the North. 



Olea. Oleacece. 



The ornamental species are grown from cuttings of mature shoots, 

 either under frames or in the border, and also by seeds. For propa- 

 gation of 0. europcea, see Olive. 



Olive (Olea europoea). Oleacece. 



The olive is grown in large quantities from seed, especially 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, 1 or 2 

 inches in diameter, and from 1 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 boxes of sand. Chips from old trunks, 



