PI S 



OR, BOTANICAL DICTIONARY. 



P I S 



341 



when the weather is very dry, and are continued till the end 

 of September. Mastich is a resinous substance, imported into 

 England in small, yellowish, transparent, brittle grains or 

 tear,s ; it has a light agreeable smell, especially when rubbed 

 or heated : on being chewed, it first crumbles, soon after 

 sticks together, and becomes soft and white like wax, without 

 impressing any considerable taste. It totally dissolves, except 

 the earthy impurities, which are commonly in no great quan- 

 tity, in rectified spirit of wine, and then discovers a degree of 

 warmth and bitterness, and a stronger smell than that of the 

 resin in substance. Boiled in water, it impregnates the liquor 

 with its smell, but gives out little or nothing of its substance: 

 distilled with water, it yields a small quantity of a limpid es- 

 sential oil, in smell very fragrant, in taste moderately pungent. 

 Rectified spirit brings over also in distillation the more vola- 

 tile odorous matter of the mastich. It is a common practice 

 with the Turkish women to chew this resin, especially in the 

 morning, not only to render their breath more agreeable, 

 but to whiten the teeth, and strengthen the gums ; they also 

 mix it with their fragrant waters, and burn it with other 

 odoriferous substances in the way of fumigations. European 

 japanners also employ it in some of their varnishes. As a 

 medicine, it is thought to be a mild corroborant and astrin- 

 gent; and, as possessing a balsamic power, it has been recom- 

 mended in haemoptysis proceeding from ulceration, fluor 

 albus, debility of the stomach, and in diarrhoeas and internal 

 ulcers. Chewing it has been also said to be of use in pains 

 of the teeth and gums, and in some catarrhal complaints. 

 There is a variety called the Narrow-leaved Mastich Tree, 

 which rises to the same height, but differs in having a pair 

 or two of leaflets more to each leaf, which is much narrower, 

 and of a paler colour. Native of the country about Mar- 

 seilles, and some other places in the south of Europe. 

 The plants of this species are generally propagated by laying, 

 down their young branches, which, if properly managed, will 

 put out, roots in one year, and may then be cut off from the 

 old plants, and each transplanted into separate small pots. 

 These must be sheltered in winter, and placed abroad in a 

 sheltered situation, and treated in the same way as other 

 hardy green-house plants. It may also be raised by seeds 

 in the same way as the others; but if the seeds be not taken 

 from trees growing in the neighbourhood of the male, they 

 will not grow ; and if they are kept out of the ground till 

 spring, the plants rarely appear till the spring following. 

 When these plants have obtained strength, some of them 

 may be turned out of the pots, and planted against warm 

 walls, where, if their branches be trained against the walls, 

 they will endure ordinary winters very well, and may be pre- 

 served with a little shelter when the winters are severe. 



Pistia; a genus of the class Monadelphia, order Oct- 

 andria. GENERIC CHARACTER. Calix : . none. Corolla: 

 one-petalled, unequal, erect, permanent; tube short, closely 

 embracing the germen ; border cordate, roundish, widened, 

 acuminate, entire, contracted in the middle on both sides by 

 a lateral plait bent inwards. Stamvta: filamentum round, 

 thick, blunt, springing almost perpendicularly from the centre 

 of the border of the corolla, hanging, over the pistil, sur- 

 rounded at the base by a membranaceous disk, and augment- 

 ed below on both sides by a fringe hanging down, the width of 

 the antheree; anthers six to eight, globular, placed in a ring 

 round the margin of the filamentum at the top; (Swartz says, 

 hree to eight, and generally three only.) Pistil: germen 

 subovate, twice as long as the tube of the corolla, fastened 

 to the back of the petal by a longitudinal thickened line, 

 extending to the very origin of the filamentum ; style thick, 

 rect, shorter than the filamentum; stigma blunt, subpeltate. 



Pericarp : capsule ovate, compressed, 'one-celled. Seeds : 

 very many, oblong, depressed at the top, and there umbi- 

 licated with a dot, inserted horizontally to the back of the 

 capsule, where it adheres to the corolla. Observe. This 

 plant was placed by Linneus in the class Gynandria; but 

 Swartz, after Jacquin, has placed it better in that of Mon- 

 adelphia. ESSENTIAL CHARACTER. Calix: none. Co- 

 rolla: one-petalled, tongue-shaped, entire. Antheree: six or 

 eight, placed on the filamentum. Style: one. Capsule: one- 

 celled, at the bottom of the corolla. The species are, 



1. Pistia Stratiotes. This is a stemless floating elegant 

 plant; roots many, a foot and half long, putting forth simple 

 fibres from their circumference, an inch and half in length. 

 Leaves various in number and size, according to the age of 

 the plant, (while it is in vigour, about twenty,) spreading out 

 in a circle or like a rose, a foot in diameter : they are ob- 

 ovate, attenuated at the base, for the most part quite entire, 

 sometimes emarginate, sessile, patulous, lanuginose at the 

 base between the nerves, and ,on the upper surface villose, 

 thick, spongy, a little succulent, and therefore well adapted 

 for floating; but on the back, from a thicker, very large, and 

 subovate area, they push forth ascending, very thick, and 

 extremely prominent nerves. Flowers whitish, inodorous, 

 axillary, solitary, and erect, on a short peduncle. Adanson, 

 in his History of Senegal, asserts that the primary root is fixed 

 strongly into the bank. Jacquin did not attend to this cir- 

 cumstance, but remarks, that in taking the plants out of the 

 water, he never found any resistance ; though he does sug- 

 gest that the young plant may be fixed at first, and after- 

 wards break loose. Native of Asia, Africa, South America, 

 and the West Indian Islands, in stagnant waters and quiet 

 streams ; flowering in April. 



2. Pistia Spathulata. Leaves upon the petiole, abruptly 

 angustated, dilatated above, rotund-obtuse ; flowers white, 

 axillary. Grows in Carolina. 



Pisum; a genus of the class Diadelphia, order Decandria. 

 GENERIC CHARACTER. Calix: perianth one-leafed, five- 

 cleft, acute, permanent; the two upper segments broadest. 

 Corolla: papilionaceous; standard very broad, obcordate, 

 reflex, emarginate with a point; wings two, roundish, con- 

 verging, shorter than the standard ; keel compressed, semi- 

 lunar, shorter than the wings. Stamina: filamenta in two dis- 

 tinct sets; one simple, superior, flat, awl-shaped ; and nine 

 awl -shaped, below the middle united into a cylinder, which 

 is cloven at top; antherse roundish. Pistil: germen oblong, 

 compressed ; style ascending, triangular, membranaceous, 

 keeled, with the sides bent outwards ; stigma growing to the 

 upper angle, oblong, villose. Pericarp : legume large, 

 long, roundish, or compressed downwards, with the top acu- 

 minate upwards, one-celled, two-valved. Seeds: several, 

 globular. ESSENTIAL CHARACTER. Style: triangular, 

 above keeled, pubescent. Calix : has the two upper seg- 

 ments broadest. -The species are, 



1. Pisum Sativum; Common Pea. Petioles round; sti- 

 pules rounded at bottom, and crenate ; peduncles many- 

 flowered. . Root annual, slender, fibrous; s f ems hollow whilst 

 young, brittle, branched, smooth, weak, climbing by termi- 

 nating tendrils ; leaves abruptly pinnate, composed usually 

 of two pairs of leaflets, which are oval and smooth ; corolla 

 white, greenish white, purple, or variegated; legumes com- 

 monly in pairs, about two inches long, of an oblong form, 

 smooth, swelling at the straight suture where the seeds are 

 fastened, flatted next the other suture, which arches. espe- 

 cially towards the end; seeds from five or six to eight or 

 nine, commonly globular, but in some varieties irregular, or 

 approaching to a cubic form, smooth, white, yellow, blue, 



