634 CLXX1X. POLYGONE^C. 



Polygo)iete are clearly separated from all the Cyclospermeee with farinaceous albumen by their ortho- 

 tropous ovule and antitropous embryo. They are further distinguished from Chenopodece and Amaran- 

 tacece by their ternary floral whorls, the often coloured perianth, and the prevalence of the ochrea. The 

 tribe of Eriogoneee, the flowers of which have an involucre, approach nearer to Phytolnccets, but are 

 separated by the superior radicle. Polygonca; are also connected with Caryophytteee through Paroriychiedff 

 and have also some affinity with Plumbar/tnete (which see). 



Polyyonete mostly inhabit the north temperate hemisphere ; they are less frequent in the tropics. 

 They are frutescent or arborescent in Central America, and become rare south of the tropic of Capricorn. 

 The tribe of Erioganea is principally North American and Chilian, Brunnichia inhabits Carolina, and 

 Antiffonwn Mexico. The Rhubarbs (R/tci<m~) grow on the mountains of Central Asia and North 

 India. The woody genera Calligonum and Atraphaxis (Trctgopynim), grow in the plains of Central 

 Asia. Coccdoba, Triplaris, &c., are large trees of tropical America; Kcenigia, a minute herb [and 

 O.iym/], are sub-arctic and arctic. The numerous species of Polygon-um and liume.v are scattered every- 

 where, from the sea-shore to the enow-line. [Muhlenbcckia is Australian, Symineria and Rnprecktia 

 Brazilian.] 



The properties of the genera of Polyt/ntieee sustain their affinities. Their herbage contains oxalic, 

 citric, and malic acids, and is edible or medicinal. The seeds of some abound in starch, the root of most 

 contains astringent matters, sometimes combined with a resinous principle to which they owe medicinal 

 properties that have been recognized from the highest antiquity; the most important of these is 

 l{htibarb, which id distinguished from all other purgatives by its restorative action on the functions of the 

 stomach ; it is further an antidysenteric and vermifuge. The botanical history of the Rhubarb J is obscure; 

 in the tenth century the Arabs received it from the Chinese, and spread it through Europe, but the Chinese 

 only vaguely indicated its habitat, and botanists have long doubted to what species it belongs. The 

 root of Rheum amtrale, a Himalayan species cultivated at Calcutta, has the decided smell and bitter- 

 tonic taste of the roots the Chinese sell to the Russians, and like it it grates under the teeth ; added 

 to which, the form of its leaves agrees with the description which the natives of Bokhara gave of the 

 true Rhubarb to the illustrious naturalist Pallas. Rheum PJutponticum, the species originally known to 

 the ancients as Rha, grows wild in ancient Thrace and on the shores of the Euxine ; it was called later 

 Rha-poHticum, to distinguish it from the Scythian Rhubarb, which they called Rha-barbamm, whence 

 our name of Rhubarb. In Europe, and especially in Germany and England, several varieties of 7?. 

 Rhapvnticum and R. tmdulattim are cultivated on account of the pleasant acid taste of their leaves, the 

 petiole and principal nerves of which are used in tarts and preserves. [The root of the former furnishes 

 the English medicinal Rhubarb, and is extensively grown, both as a substitute for the Oriental, and 

 also to adulterate it. ED.] 



Rumex is divided into two distinct groups : the one the Sorrels (R. Acetosa, ttcutattw, &c.), containing 

 oxalate of potash in the stem and leaves, whence their acid taste and their use as food and their laxative 

 properties ; their root is red and scentless. The others, the Docks (R. patientia, crispw, aquations, &c.), 

 have yellow and scented bitter roots containing sulphur, which are used as depuratives and anti- 

 scorbutics. 



Some indigenous Polygona (P. Bistorta, Ifydropiper, Persicaria, aviculare, amphibiuni), were formerly 

 used medicinally, but all have fallen into disuse except the Bistort (P. Bistorta), the .twisted root of which 

 is an astringent tonic. P. stypticiim is in great repute in Brazil on account of the astringent properties of 

 the herbage and root. The natives of Colombia employ a decoction of P. tamnifulhun for haemorrhage. P. 

 perfoliatum is outwardly applied in Cochin China for tumours and skin diseases. P. coctimchmense, 

 administered as a topic and a drink, is considered to be an efficacious remedy for swellings of the knee, a 

 common and obstinate disease in Cochin China. The tuberous root of P. mitUiflorum is a reputed cordial 

 in Japan. P. Juemwrhoulale contains an acrid principle, and is used by the Brazilians as a condiment, 

 and as a topical application, or in baths, for rheumatic pains. 



Buckwheat (Fogopyrmn esculentum), or Black Wheat, is valuable for the abundant and excellent 



1 Within the last two years the true Rhubarb plant has been introduced into France by the Chinese 

 missionaries in East Tibet, and named R. officinale, Baillon. Eu. 



