RHUBARB 303 and cook readily to a pulp, which with sugar is used for pies, tarts, and other culinary prep- arations ; their acidity is due in part to oxalic, but more largely to malic acid, both acids be- ing in combination with potash as acid salts; it disagrees with some, but its large consump- tion indicates that it is not especially deleteri- ous. About 1860 great efforts were made to establish its use as a wine plant, but the pro- duct proved inferior, and was by many con- sidered injurious. There are several garden varieties, as at one time many seedlings were raised with a view to produce plants with the greatest development of leaf stalk ; the Gaboon has stalks 3 in. or more in diameter and often 2 ft. long, but it is coarse and harsh in flavor ; the best variety is Myatt's Linnaeus, very early, of medium size, tender, and of excellent flavor ; Tobolsk is a small kind, very early and good. For field culture the plants are raised in a seed bed, and when a year old are transplanted to 3 or 4 ft. each way; they yield the third year; small plantings are made by dividing the old roots into as many pieces as they have buds, and setting out the pieces ; the soil can hardly be too rich. Rhubarb is readily forced by placing the plants in winter in boxes or barrels with earth in a warm cellar, or on a larger scale in frames. In the present style of sub- tropical gardening the rhubarbs are employed on account of their vigor of growth and pic- Himalayan Rhubarb (Rheum nobile). turesqueness ; an isolated plant of the com- mon rhubarb is very effective, but the Nepaul rhubarb (S. Emodi) is much finer ; the leaves 704 VOL. xiv. 20 are a yard across, and have red veins ; this is cultivated in England by gardeners for the sake of its large leaves, which are used for covering baskets of fruit. The finest of all the species is the Himalayan (R. nobile), dis- covered by Dr. J. D. Hooker ; it forms a pyra- mid a yard and more high, the base of which is of shining green leaves with red petioles and nerves, and the upper parts of delicate straw- colored bracts with pink edges. Rhubarb as a drug has been known from very early times, Medicinal Rhubarb (Rheum officinale). and it is said to be treated of in a Chinese her- bal written about 2700 B. C. European natu- ralists early endeavored to ascertain the exact species that produced the excellent kinds of rhubarb procured through Russia and Turkey, and distinguished by the name of either one of these countries. Several species of rheum have from time to time been regarded as fur- nishing the better sorts; it is probably pro- duced by different species, one of which is R. officinale; this is much larger than the gar- den rhubarb, differing among other characters in having nearly cylindrical petioles, and the under side of the leaf being covered with short, erect hairs. Formerly the best variety was known as Turkey rhubarb, being brought by caravans from Tartary by way of Persia to the Levant ports, whence it reached Eu- rope ; but rhubarb from this source disap- peared from the trade about a quarter of a century ago. A similar article entered com- merce by way of Russia, and was known as Russian rhubarb. It was brought to the fron-
