250 THE NURSERY-BOOK. 



Pinckneya, Pinknea. Rubiacece. 



Seeds. Cuttings of the ripened shoots under glass. 



Pine-apple {Ananas sativa}. Bromeliacea. - 



Pine-apples very rarely produce seeds, but when they are 

 produced they are sown for the purpose of obtaining new va- 

 rieties. The pine-apple is usually increased by suckers and 

 "crowns." If the root is left in the ground after the pine is 

 removed, suckers will start from it. The root is then taken 

 up and cut into as many pieces as there are suckers, each 

 piece being then permanently planted. The crown of the 

 fruit and the various offsets or "crownlets, " which appear 

 on the sides and base of the fruit, may be removed and used 

 as cuttings. These offsets are commonly used in greenhouse 

 propagation. It is the usual practice to allow them to dry 

 several days before they are planted, and in pine-apple re- 

 gions they are often exposed to the sun for several weeks. 

 This operation is unnecessary, however, although it is not 

 objectionable.. A good way to start the offsets is to pull off 

 the lowest leaves and insert the offsets in damp moss in shade 

 giving bottom heat for greenhouse work and as soon as 

 roots begin to form, which will occur in from two to six 

 weeks, plant them out permanently. In the tropics fruit can 

 be obtained in 20 months after the offsets are transplanted ; 

 but fruit bearing is often delayed three or four years under 

 poor treatment. 



Piney. See Paeonia. 



Pinguicula (Butterwort). Lentibulariece ; 



The hardy and greenhouse species are increased by seeds 

 divisions, or by leaf cuttings. 



Pink (Dianthus, various species). Caryophyllece. 



Seeds and divisions. Best results are obtained by raising 

 new plants from seed every two or three years. Seeds are 

 usually sown where the plants are to remain ; or they may 

 be sown in a cold-frame and transplanted. 



Pinus (Pine). Conifer ce. 



Seeds, which should be kept dry over winter, are com- 

 monly employed. These are often started in pots,, but for 

 most species they are sown in well prepared beds out-doors. 

 The seedlings must usually be shaded the first season. Va- 

 rieties, as also species which do not produce seed freely, may 

 be grafted upon stocks of white or Austrian pine or other 

 species. This grafting may be done upon the tips of grow- 



