170 



rica, and Asia, they fill the ditches, hedges, and waste grounds, in the form 

 of Docks and Persicarias ; the fields, mountains, and heaths, as Sorrels and 

 trailing or twining Polygonums ; in South America and the West Indies 

 they take the form of Coccolobas or sea-side grapes ; in the Levant, of 

 Rhubarbs; and even in the desolate regions of the North Pole they are found 

 in the shape of Oxyria. 



Properties. Sorrel on the one hand, and Rhubarb on the other, may 

 be taken as the representatives of the general qualities of this order. While 

 the leaves and young shoots are acid and agreeable, the roots are universally 

 nauseous and purgative. To these two qualities is to be superadded a 

 third, that of astringency, which is found in a greater or less degree in the 

 whole order, but which becomes in Coccoloba uvifera so powerful as to 

 rival Gum Kino in its effects. Some of the Polygonums are extremely 

 acrid, as the P. Hydropiper, which is said to blister the skin. There is a 

 species of Polygonum, called Cataya in the language of the Brazilian In- 

 dians, an infusion of the ashes of which is used to purify and condense the 

 juice of the sugar-cane. It has a very bitter peppery taste, and is employed 

 on the Rio St. Francisco with advantage in the disease called O Largo, which 

 is an enlargement of the colon, caused by debility. Pr. Max. Trav. 71. 

 The stem of the Rheum has been supposed to contain a peculiar acid called 

 the rheumic, but this is now known to be the oxalic. Turner, 641. Rumex 

 acetosa contains pure oxalic acid. Ibid. 623. The principle in which the 

 active property of Rhubarb exists is supposed to be a peculiar chemical 

 substance called Rhubarbarin, Ibid. 701. Some information may be found 

 upon the Rhubarbs of India in the Trans, of the Med. and Phys. Soc. of 

 Calcutta, 3. 438. by Dr. Royle; but nothing certain had been collected by 

 him with regard to the plant producing the true ofliicinal substance. Many 

 species of Polygonum are used in dyeing. The seeds of P. fagopyrum and 

 tataricum are used as food, for the sake of their mealy albumen ; those of P. 

 aviculare are said to be powerfully emetic and purgative; but this is doubted 

 by Meisner. Man. 49. The seeds of Polygonum barbatum are used as 

 medicine by Hindoo practitioners, to ease the pain of griping in the colic. 

 Ainslie, 2. 2. The leaves of P. hispidum are said by Humboldt to be sub- 

 stituted, in South America, for Tobacco. N. G. and Sp. 2. 178. 



Examples. Rheum, Rumex, Coccoloba. 



CLVII. BEGONIACEiE. 



BEGONiACEiE, R. Browii ill Congo, 404. (1818); Link Ilandb. 1. \Wd. (1829); Martins 



II. Reg. Man. {U]2'J.) 



Diagnosis. Apetalous dicotyledons, with a 3-celled winged ovarium, 

 indefinite ovules, an irregular imbricated calyx, and membranous stipulac. 

 Anomalies. 



Essential CiiauaCTER Flmrcrs unisexual. Sepals superior, coloured; in the 



males 4, 2 within the others and smaller; in the females T), imbricated, two smaller than 

 the rest. Stamens indefinite, distinct or combined into a solid column ; anthers collected 

 in a head, 2-celled, continuous with the filaments, davate, the connectivum very thick, the 

 cells minute, hurstinff longitudinally. Oriirhim inferior, winj^ed, li-celled, with ;{ double 

 polyspermous placent* in the axis ; sliiimns ;{, 2-lol)e(l, sessile, somewhat spiral. Fruit 

 membranous, capsular, winged, .'{-celled, with au indefinite number of minute seeds; 

 bursting by slits at the base on each side of the wings. Seeds with a transparent thin 

 testa marked by reticulations, which are olilong at the si<les and contracted at either extre- 

 mity; embryo very cellular, without albumen, with a blunt round radicle next the hilum. 

 — Herbaceous ]ilants or uudcr-shrubs, with an acid juice. Leaves alternate, toothed, 

 obliipic at the base. Stipulcc scarious. Flowers pink, ia cymes. 



