THE NURSERY LIST. 255 



Polycarpaea. Caryophyllece. 



The annuals are increased by seeds ; perennials by cuttings. 

 Polygala (Milk wort). Polygalece. 



Seeds; sometimes by division, and by cuttings of young 

 shoots under cover, particularly for tropical species. 



Polygonatum (Solomon's Seal). Liliacece. 



Propagated by seed and by divisions. 

 Polygonum (Knot- Grass or Weed). Polygonace'ce. 



Seeds. The perennials are also increased by divisions of 

 the root-stocks, and by cuttings. 



Polypodium (Polypody). Filices. 



Divisions usually. See Ferns. 

 Pomegranate (Punita granatum}. Lythrcenece. 



Largely by seeds, and all varieties are increased by cut- 

 tings, suckers, layers, and scarce sorts by grafting on a com- 

 mon sort. 



Pomelo, Shaddock (Citrus Aurantium, var. pomelana]. Rutacece 

 Usually grown from seeds, but it may be budded upon po- 

 melo or orange stocks, as in the Orange, which see. 



Pontederia (Pickerel Weed). Pontederiacece. 



Seeds rarely. Mostly by divisions. 

 Poppy. See Papaver. 

 Populus (Poplar, Aspen, Cotton-wood). Salicinece. 



Seeds, sown as soon as ripe and raked in in light soil. Suck- 

 ers are also used. Most often increased by cuttings of ripe 

 wood, taken in fall and spring. The weeping forms are 

 .' stock-grafted upon upright sorts, as P. grandidentata. 



Portugal Laurel. See Prunus. 



Portulaca (Purslane, Rose Moss). Portulacece. 



The annuals are raised from seed. Varieties are some- 

 times propagated by cuttings. 



Potato (Solanum tuber osuni). Solanacece. 



Tubers, either whole or variously divided. Also rarely 

 stem cuttings. (See page 52.) 



Potentilla, including Horkelia, Sibbaldia (Cinquefoil, Five- 



Finger). Rosaccw. 

 Seeds, layers, divisions, green cuttings. 



