ENCYCLOPEDIA OF GARDENING. 
Piptanthus (Nepaul Laburnum).—Ord. Leguminose. Hardy 
evergreen flowering shrub. J irst introduced 1821. 
CULTURE: Soil, rich sandy loam. Position, warm sheltered shrub- 
beries, 8. & S.W. 6f England; against S. walls, N. of London. Plant, 
Sept., Oct., April, or May. Prune straggling shoots moderately after 
flowering. Propagate by seeds sown in sandy soil in cool greenhouse 
or cold frame in spring; cuttings of ripened shoots inserted in small 
Tone of sandy soil under bell-glass or hand-light outdoors, Aug. or 
Sept.; layering shoots, Sept. or Oct. 
SPECIES OULTIVATED: P. nepalensis, yellow, summer, 5 to 10 ft., Himalayas. 
Pirstachio-nut (Pistacia vera).—See Pistacia. 
Pistacia (Pistachio-nut Tree; Mastich Tree)—Ord. Anacar- 
diacee. Hardy evergreen & deciduous trees. Flowering & orn. 
foliage. First introduced 1656. Leaves, unequally feather-shaped, 
green; reddish in young state. 
CULTURE: Soil, deep rich sandy loam. Position, sheltered shrub- 
beries S. & S.W. England; against S. walls, N. of London. Plant 
evergreen species, Sept., Oct., April, or May; deciduous species, Nov. 
to Feb. Prune evergreen species, April; deciduous species, Nov. to 
Feb. Propagate by cuttings inserted in sandy soil in cold frame or 
under hand-light, Sept. or Oct.; layering in Sept. 
SPECIES CULTIVATED: P. atlantica, leaves pinnate, evergreen, 40 ft., Canary 
Isles; Lentiscus (Mastich Tree), leaves pinnate, 20 ft., S. Europe; Terebinthus 
(Turpentine Tree), yellow, June, 30 ft., 8. Europe; vera (Pistachio Nut Tree), 
brown, April, 20 ft., Syria. 
Pistia (Tropical Duck Weed; Water Lettuce).—Ord. Aroides. 
Stove aquatic perennial. First introduced 1843. Flowers, green, 
borne on spadix at base of leaves. Leaves, wedge-shaped, notched, 
pale green, hairy. 
CULTURE: Soil, rich loam. Position, shallow tub or tank in 
stove. Place 2-in. layer of soil on bottom of tub or tank & plant on 
surface of water. Replenish with tepid water occasionally. Add 
fresh soil annually. Temp., March to Oct. 70° to 85°; Oct. to March 
60° to 70°. Propagate by offsets. 
SPECIES CULTIVATED: P. stratiotes, 1 to 3 in., Jamaica. 
Pisum (Garden Pea; Sugar Pea; Crown or Mummy Pea).—Ord. 
Leguminose. Hardy annuals. Edible seeded & pedied vegetables. 
CULTURE OF GARDEN PEAS: Soil, deep, rich calcareous loam, 
previously trenched three spits deep & containing a thick layer of 
manure between first and second spit. Position, open sunny, pro- 
tected from N. & N.E. & E. winds. Suitable Manures: Solid—Horse 
dung or peat-moss litter for heavy soils; cow or pig dung for light or 
sandy soils. Chemical—(1) Kainit 2lb., nitrate of soda 5l1b., super- 
phosphate of lime 91b., half of each to a square rod before sowing, 
remainder when plants are 6in. high; (2) nitrate of soda 1}1b., kainit 
1}1b., superphosphate 1}1b., salt 3]b., applied same as No. 1; 
(3) native guano 6lb. to a square rod applied before sowing, & 6 1b. 
when plants are 3in. high; (4) Peruvian guano 11b. for square rod 
before sowing, also 11b. when plants are 3in. high. Liquid—Horse 
& cow urine diluted with two-thirds water; nitrate of soda }oz. to 
gallon, all to be applied when ground is moist only & when pods have 
just formed. Direction of rows: E. to W. or S.E. to N.W. for early 
sorts; N. to 8. for main crops. Depth of drills, 2} to 3in.; width, 
6 to Yin. Distance apart for sowing the seeds: lin. each way for 
dwarf sorts; 2in. for medium kinds; 3in. for tall vars., arranged in 
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