1358 



PIQUERIA 



PISTIA 



white-edged leaves (var. variegata, Hort., Pig. 1834), 

 which are much used for bedding out. The Piqueria 

 endures both sun and shade, and thrives with even in- 

 different treatment. For flowers, it is much prized in 

 winter, when delicate white sprays are not abundant. 

 It demands the general treatment given zonal gera- 

 niums. Prop, by cuttings with great ease, and begin- 

 ning to bloom when only 2 or 3 in. high. It often blooms 

 in the cutting-bed. It also grows readily from seeds, 



1833. 



Piqueria trinervia (X %). 



Known to florists as 



Stevia serrata. 



1834. 



Marginate form of Piqueria 

 trinervia. 



which are handled by seedsmen. Frequent pinching 

 will keep the plants within bounds and contribute to 

 floriferousness. Plants allowed to grow as they will 

 soon become straggly and wiry. For winter bloom the 

 plants may be handled in pots or grown in beds. A 

 stock of compact pot-plants kept in a cool corner is very 

 useful for filling vacancies in the house. 



Piqueria trinervia is native in Mexico. It is per- 

 ennial. B. M. 2650. The genus contains about 10 species 

 of herbs or bushes, all of tropical America. The heads 

 contain 3-5 whitish tubular fls. : torus plane or convex, 

 naked: pappus none or very short: akene 4-5-angled. 



L. H. B. 



Usually the best way to manage to produce good flow- 

 ering plants of Stevia in midwinter is to save a few 

 old plants after the flowers are cut at New Years. Cut 

 off the old stems 5 or 6 inches above the pots and stand 

 the plants in any cool house. The plant .needs the cool- 

 est house at all times ; 40 at night during the winter 

 will grow it better than a higher temperature, but, for 

 all that, it does not endure the slightest frost. About 

 March 1, these old plants will have sent out any num- 

 ber of small growths from the base of the stems. 

 These root very readily in a cool propagating house. 

 They should then be grown along, first in 2- and after- 

 ward in 3-inch pots, until the first of June, when they 

 should be planted out in the open ground. It need not 

 be very rich ground, for they are very rampant growers. 

 Give every plant 2 feet of space. They seldom need 

 any artificial watering during summer, but they should 

 have frequent pinching to produce bushy plants. The 

 more shoots, the more flowers will be secured. Before 

 there is any danger of frost in the fall, the plants 

 should be lifted and put into 6-, 7-, or 8-inch pots. They 

 lift well, and if stood in the shade and kept syringed 

 for a few days they will show no bad results of the lift- 

 ing. A position at the north side of a shed or wall is 

 much better for them for the next month than under 

 glass, but always have them in a position where they 

 can be protected in case of a frost. By the end of Oc- 

 tober, if frost is escaped, put them in the lightest and 

 coolest house available. If kept cool these very desir- 

 able sprays of flowers will be in perfection at Christ- 

 mas, and that is the time they are most valuable. Al- 



though classed as a common, cheap flower, there is a 

 grace about Stevias that makes them indispensable for 

 many of our flower arrangements, and we consider them 

 a very needful florist's plant. WM. SCOTT 



PIRONNEAVA. See^chmea. 



PISClDIA (Latin, fish and kill). Legiimlndsce. A 

 genus of 1 or 2 species, including the Fish-poison tree 

 of the American tropics, or Jamaica Dogwood. The 

 leaves, bark and twigs of this tree when thrown into 

 the water intoxicate or stun the fish so that they can 

 be caught readily. (For the plant used in China for 

 this purpose, see Cocculus.) The bark has also been 

 used in medicine for its hypnotic effect. Botanically 

 this genus is close to Lonchocarpus, differing mainly 

 in the pod, which is long, thickish and longitudinally 

 4-winged. Generic characters : calyx-teeth 5, short, 

 broad : wings adhering to the falcate keel : vexillar sta- 

 men free at the very base, but grown together at the 

 middle with the others into a closed tube: ovary ses- 

 sile, many-ovuled. 



Erythrina, Linn. FISH-POISON TREE. JAMAICA DOG- 

 WOOD. Lfts. 7-11, opposite, oblong or elliptical, pointed 

 or blunt: fls. purplish white, % in. across: pod 2-4 in. 

 long, 4 lines broad; seeds 6-8, black. Trop. Amer., es- 

 pecially common in Jamaica. 



PISTACHIO. See Pistacia. 



PISTACIA (derived indirectly from ancient Persian 

 pista). Anacardiacece. P. vera produces the Pistachio- 

 nuts of commerce, which are much used in confection- 

 ery and flavoring. The so-called nut is really the seed 

 or kernel of a dry drupe. The seed is green, and has a 

 highly peculiar flavor. P. Terebinthus exudes from its 

 stem the fragrant Cyprian or Scio-turpentine used in 

 medicine as early as the time of Hippocrates. Pistacia 

 is a genus of about 10 species of trees, found from the 

 Mediterranean region to Afghanistan, with 1 species in 

 the Canaries and 1 in Mexico. Lvs. alternate, evergreen 

 or deciduous, odd-pinnate: fls. small, in axillary pani- 

 cles or racemes, dioecious and without petals; males 

 with 5-cut calyx and 5 stamens; females 3-4-cut and 

 with 3-cut style: ovary 1-celled. Engler, DC. Monogr. 

 Phaner. 4:284-293 (1883). 



vera, Linn. PISTACHIO-NUT. Small tree attaining 20 

 ft. : Ifts. 3 or 5: fr. large, oblong, acute. Mediterranean 

 region and Orient. Cult, in S. California, Calif. May 

 be grafted on P. Terebinthus. 



P. Terebinthus, Linn. A small turpentine-producing tree: 

 Ifts. 9-13, mucronate; petiole not winged: stamens pink: stig- 

 mas red: fr. small, roundish. Southern Europe, Mediterra- 

 nean region. In the European form the terminal 1ft. is about 

 as long as the others, but in the oriental form it is mimtte or 

 lacking. Mentioned in the lists of Amer. Pomological Society 

 as a cultivated fruit, as is also P. vera. 



PlSTIA (probably from Greek, pistos, watery; refer- 

 ring to its aquatic nature). Ardcece. WATER LETTUCE 

 or TROPICAL DUCKWEED is a small, tender, perennial 

 floating herb desirable for aquaria. It forms a loose 

 rosette of Ivs. and has long, slender, feathery roots. 

 The plant sends out runners on which may sometimes 

 be seen young plants in all stages of development. A 

 healthy plant measures about 6 in. across. The Ivs. are 

 generally more or less wedge-shaped, 2-5 in. long, pea- 

 green, velvety to the touch, and covered beneath with a 

 sort of mealy down. The Pistia rosette has been com- 

 pared to a half -grown lettuce plant before the head has 

 formed. Like many other aquatics, the Water Lettuce 

 has an immense range. It is found in fresh waters 

 throughout the tropics, and in America is said to be 

 native as far north as North Carolina. 



Water Lettuce is commonly grown outdoors in sum- 

 mer in collections of tender aquatics, and also in 

 aquaria. The summer temperature of the water should 

 be 70-80 F. Although it grows well when floating free 

 in several feet of water, it seems to do better when 

 placed in shallow water where the roots may reach the 

 soil. Larger-sized plants may be secured by using a 

 thin layer of rich soil or well-rotted manure in the 

 bottom of the vessel. Soft water is said to be essential. 

 Running water is not necessary. The plants should be 



