poly] 



Et)e ErfaSurj? at SSotany. 



914 



indigo; its seeds are a vermifuge. Theroot 

 of P. thesioides has diuretic properties. P. 

 venenata, a Javanese plant, is reported to 

 be intensely poisonous ; merely touching 

 a leaf of this plant is sufficient to produce 

 violent sneezing and faintness, according 

 to Commerson. 



Of all the species, however, which are 

 used medicinally, that best known in this 

 country is P. Senega, the root of which is 

 used as a stimulant diaphoretic and expec- 

 torant, especially in cases of chronic bron- 

 chitis. In large doses it produces symp- 

 toms of acrid poisoning. The root, as met 

 with in commerce, is remarkable for having 

 a prominent ridge extending along its 

 whole length on one side. The active pro- 

 perties appear to depend upon an acid sub- 

 stance found principally in the rind of the 

 root, and called polygalic acid, or some- 

 times senegin. This root was introduced 

 into medical practice by Dr. Tennant, a 

 Scotch physician residing in Pennsylvania, 

 as a remedy for snake-bites. Several other 

 species, besides many of those already men- 

 tioned, are described as having similar 

 virtues as antidotes to snake-bites. They 

 seem to act as stimulant emetics, purga- 

 tives, and diaphoretics, and relieve the 

 embarrassed breathing which occurs in 

 such cases. 



Several species are in cultivation as 

 greenhouse plants, P. cordifolia, P. latifolia, 

 and P. opposittfolia, all Cape species, being 

 among the handsomest. The purple petal- 

 like sepals and fringed keel-like petal give 

 these plants a singular and elegant appear- 

 ance. P. Chamabuxus is a dwarf-growing 

 evergreen shrubby species, with compara- 

 tively large yellow flowers. It grows wild 

 in Central Europe, and is frequently met 

 with in the borders of shrubberies, &c. P. 

 vulgaris is a common British plant, espe- 

 cially on chalky or limestone soil. Its 

 branches are numerous, slender, ascending, 

 clothed with more or less linear leaves, the 

 lowermost obovate or even roundish, and 

 bearing flowers of a bright-blue or some- 

 times pink or white. P. amara is generally 

 considered as a mere variety of P. vulgaris, 

 which indeed differs very much in the 

 shape of the leaves and sepals, their colour, 

 &c. in different situations. [M. T. M.] 



POLYGAMOUS. Having, on the same 

 plant, some flowers male, others female, 

 and others hermaphrodite. Its 'sign is 



POLYGONACE^E. (Buckivlieats.) A na- 

 tural order of monochlamydeous dicotyle- 

 dons, belonging to Lindley's silenal alli- 

 ance of hypogynous Exogens. They are 

 herbaceous, rarely shrubby plants, with 

 alternate stipulate or exstipulate leaves, 

 and often unisexual flowers. Perianth in- 

 ferior, often coloured ; stamens definite, 

 inserted into the bottom of the perianth ; 

 ovary free,usually formed by three carpels ; 

 ovule solitary, orthotropal ; styles and stig- 

 mas equal to the carpels in number. Fruit 

 a nut, usually triangular, naked or covered 

 by the persistent perianth ; seed erect, 

 with farinaceous albumen. They are found 



in almost all parts of the world, more es- 

 pecially in the temperate regions of the 

 northern hemisphere. They grow in fields, 

 waste grounds, ditches, mountains, &c, 

 and have astringent and acid properties- 

 some being purgative, and a few acrid. 

 Their astringency depends on the presence 

 of tannin, and their acidity chiefly on oxa- 

 lic acid. The fruit of Polygonum avicu- 

 lare is emetic and purgative. The fruit 

 of Fagopyrum esculentum, and other spe- 

 cies of buckwheat, is used as food ; the 

 plant is cultivated in some northern coun- 

 tries. The leaves of Rumex Acelosa, sorrel, 

 and of R. Acetosella, field sorrel, are acid 

 and astringent. The roots of Rumex aqua- 

 ticus, and R. Eydrolapathum, the water 

 docks, and of other species, are used as as- 

 tringents and alteratives ; those of R. alpi- 

 niis, under the name of Monk's Rhubarb, 

 were formerly employed as purgatives. 

 One of the most important plants of the 

 order is the rhubarb plant. [J. H. B.] 



POLYGON ATUM. The Solomon's Seal : 

 a genus of liliaceous but not bulbous plants, 

 with axillary cylindrical six-cleft flowers, 

 the stamens inserted in the top of the tube, 

 and the fruit a globose three-celled berry 

 with two seeds in each cell. P. multijlorum, 

 the most frequent species in England, 

 grows profusely in certain situations where 

 it has taken possession of tne soil, but can- 

 not be called a common plant. It sends up, 

 to the height of about two feet, stoutish j 

 simple green stems, of which the lower 

 half is bare of leaves, the upper curved 

 towards a horizontal direction, and bearing 

 numerous broad sessile leaves ; and from 

 their axils slender flowerstalks with droop- 

 ing green and white flowers in clusters of 

 two to four. These are succeeded by small 

 bluish-black terries. Less frequent spe- 

 cies are P. verticillatum, found in Scotland, 

 which bears its leaves in whorls ; and P. 

 officinale, resembling the first in habit but 

 smaller, and bearing solitary fragrant 

 flowers. Several foreign species are de- 

 scribed. French : Sceau de Solomon ; Ger- 

 man : Weisswurz. [C. A. J.] 



POLYGONELLA. A genus of Polygona- 

 cece, inhabiting dry plains in the warmer 

 parts of North America. Small branched 

 smooth shrubs, with short ocbreas, small 

 thick linear or spathulate subsessile leaves, 

 and small perfect or polygamous white 

 or rose-colour spicately racemose flow- 

 ers, adpressed to the rachis. Perianth 

 coloured, five-leaved, the two outer seg- 

 ments unchanging, at length reflexed, the 

 three inner enlarging and enclosing the 

 fruit, [j. T. S.] 



POLYGONUM. A very extensive and 

 generallydistributed genus of Polygonacece, 

 consisting of annual or perennial herbs, 

 more rarely undershrubs, found through- 

 out the whole world but rare within the 

 tropics. They have alternate leaves, with 

 ochreate stipules ; and the flowers are 

 usually in spikes or racemes, sometimes 

 contracted into heads, sometimes so lax 

 that they may be regarded as axillary. The 



