258 Encyclopedia of Gardening 



Phytophthora. Infestans is the fungus which causes what is 

 known as Potato blight or disease. See Kitchen Garden. 



Phytoptus. A genus of mites, Ribis (syn. Eriophyes ribis), causes 

 the " big bud " of Black Currants. See Fruit. 



Picea (pi-cea, from pix t pitch, in allusion to the resinous character. 

 Ord. Coniferae). See also Abies, to which the Piceas are closely 

 related, and Spruce. The Piceas include several important timber 

 trees, but their principal value in gardens lies in the horticultural 

 varieties of the Norway Spruce, P. excelsa, and P. pungens. These 

 are prettily tinted, are of neat habit, and grow slowly, so that they 

 are good for garden borders. Amongst the best of the Piceas for 

 garden purposes are excelsa argenteo-spica, which has silver- tipped 

 leaves; e. aurea, with gold -tipped leaves; e. diffusa, very dwarf; 

 e. pygmaea, pyramidal, dwarf; Morinda (Smithiana), one of the 

 hardiest of the Spruces, and, like excelsa, good to plant as a sheltering 

 tree ; polita, a good lawn tree ; pungens argentea, a silvery form of 

 the Blue Spruce of the Rocky Mountains; p. glauca, a graceful 

 little glaucous plant; and p. pendula, a weeping form of the pre- 

 ceding. These can all be bought from nurserymen at moderate 

 prices. The forest Spruces are sold in quantity very cheaply. 

 The Piceas are not fastidious as to soil, but deep, sandy loam is best. 

 Propagation is by seed sown in spring, but it is perhaps best left to 

 nurserymen. 



Picotee. See Carnation. 



Pieris (pi-eris, from Pieria, the home of the Muses. Ord. Erica- 

 ceae). Handsome evergreen shrubs, suitable for shrubbery borders 

 and special positions on lawns. They are naturally of compact 

 habit. They like sandy peat, and may be propagated by layers in 

 autumn. Floribunda, with white flowers in spring, is the most 

 popular (syns. Andromeda floribunda (Botanical Magazine, t. 1566) 

 and Leucothoe floribunda) . 



Pilea, Artillery Plant (pi-lea, from pilos, a cap. Ord. Urticaceae). 

 Muscosa is an interesting plant. The leaves are finely divided, 

 and the flowers are small and reddish. If sprinkled with water 

 when in full bloom, explosions follow, giving the effect of a minia- 

 ture bombardment. It likes a warm house. Loam, with sand and 

 a third of leaf mould, suits. Propagation is by cuttings in bottom 

 heat, or by seeds sown in a warm house or frame. 



Pilewort, Ranunculus Ficaria. 

 Pilocereus. See Cactus (Cereus). 



Pimelea (pime-lea, from pimele, fat. Ord. Thymelaeaceae) . A 

 genus of minor importance, but occasionally grown in large gardens. 

 With training they make handsome exhibition plants, and are seen 

 in collections of stove and greenhouse plants at some of the larger 

 exhibitions. They like equal parts of peat and loam, with a great 

 deal of sand. Propagation is by cuttings of young shoots, taken 

 with a heel in spring and inserted in sandy peat under a bell-glass 

 in a warm house. After flowering cut back to the hard wood, and 

 repot when fresh growth starts. Rosea (syn. Hendersoni), pink 



