Production and Commerce—The districts of the Chinese Empire which produce rhubarb extend over a vast area. They are comprised in the four northern provinces of China Proper, known as Chihli, Shansi, Shensi,[1832] and Honan; the immense north-western province of Kansuh, formerly partly included in Shensi, but now extending across the desert of Gobi and to the frontiers of Tibet; the province of Tsing-hai inhabited by Mongols, which includes the great salt lake of Koko-nor and the districts of Tangut, Sifan, and Turfan; and lastly the mountains of the western province of Szechuen. The plant is found on the pasturages of the high plateaux, growing particularly well on spots that have been enriched by encampments.
What little we know regarding the production of rhubarb and its preparation for the market, from Catholic missionaries,[1833] is of a rather meagre and unsatisfactory character. The root is dug up at the beginning of autumn when the vegetation of the plant is on the decline, and the operation is probably continued for a few months, or in some districts for the whole winter. It is cleaned, its cortical part sliced off, and the root cut into pieces for drying. This is performed either by the aid of fire-heat, or by simple exposure to sun and air, or the pieces are first partially dried on a hot stone, and then strung on a cord and suspended until the desiccation is complete.
According to F. von Richthofen[1834] the best rhubarb is collected exclusively from plants growing wild in the high alps of western Szechuen, especially in the Bayankara range, between the sources of the Hoang-ho and the rivers Ya-lung-Kiang and Min-Kiang. This variety is chiefly known under the name Shensi rhubarb, although the inhabitants of the province of Szechuen pretend the superiority of the drug of their own country. The important places for the commodity are Sining-fu in the province of Kansu, and Kwan-hien in Szechuen. In the plain of Tshing-tu-fu, according to Richthofen, rhubarb is cultivated in fields, but its product is stated to be much inferior to that of the true plant which is said not to succeed under culture.
Rhubarb is now purchased for the European market chiefly at Hankow on the upper Yangtsze, whither it is brought from the provinces of Shensi, Kansu, and Szechuen. From Hankow it is sent down to Shanghai, and there shipped for Europe. The exports from Hankow are stated in official documents[1835] to have amounted to the following numbers of peculs (one pecul = 133⅓ lb. = 60·479 kilogrammes):
| 1866 | 1867 | 1868 | 1869 | 1870 | 1871 | 1872 |
| 2985 | 3425 | 2866 | 3398 | 3370 | 3859 | 3167 |
In 1877 there were exported by way of Hankow 2096 peculs from Shensi and 3385 peculs from Szechuen.—From all the Chinese ports, 5124 peculs of rhubarb were shipped in 1874.
Much smaller quantities (554 peculs in 1872, 1055 peculs in 1874) are shipped from Tientsin; and there are occasional exportations from Canton, Amoy, Foochow, and Ningpo. The imports of rhubarb into the United Kingdom in 1870 amounted to 343,306 lb., the estimated value of which was £62,716.[1836]
We have no information about the rhubarb which is stated by Bellew[1837] to grow on the hills near Kayn or Ghayn in eastern Persia (about 32½° N. lat.).
Description—China Rhubarb as imported into Europe[1838] consists of portions of a massive root which display considerable diversity of form, arising from the various operations of paring, slicing and trimming, to which they have been subjected. Thus some pieces are cylindrical or rather barrel-shaped, others conical, while a large proportion are plano-convex, and others again are of no regular shape. These forms are not all found in the same package, the drug being usually sorted into round and flat rhubarb. In dimensions we find 3 to 4 inches the commonest length, though an occasional piece 6 inches long or more may be met with. The width may be stated at 2 to 3 inches. The outer surface of the root is somewhat shrivelled, often exhibiting portions of a dark bark that have not been pared away. Many pieces are pierced with a hole, in which may be found the remains of a cord used to suspend the root while drying. The drug is dusted over with a bright brownish-yellow powder, on removal of which the outer side of the root is seen to have a rusty-brown hue, or viewed with a lens to be marked by the medullary rays, which appear as an infinity of short broken lines of deep brown, traversing a white ground.
The character which most readily distinguishes the rhubarb of China is that well-developed pieces, broken transversely, display these dark lines arranged as an internal ring of star-like spots. Although this character is by no means obvious in every piece of Chinese rhubarb, it is of some utility from the fact that in European rhubarb, such spots are generally wholly wanting, or at most occur only sparingly and in an isolated manner.