UNITED STATES DEPARTMENT OF AGRICULTURE

Washington, D. C.

BULLETIN No. 706

Contribution from the Bureau of Chemistry

CARL L. ALSBERG, Chief

Issued July 26, 1918; Revised November 6, 1920.

AMERICAN SUMAC: A VALUABLE TANNING MATERIAL AND DYESTUFF.

By F. P. VEITCH, Chemist in Charge, J. S. ROGERS and R. W. FREY, Assistant Chemists, Leather and Paper Laboratory.

Sumac, known also as "shumac" or "shoemake," is a wild plant rich in tannin, a product of value to the tanning and dyeing industries. Sumac grows on uncultivated lands in many parts of the United States and is particularly abundant and accessible east of the Mississippi. Plentiful stands occur on cut-over land, in old fields and pastures, on mountain sides, in waste places, and on the edge of swamps in the Appalachian region. Immense quantities of this valuable tanning and dyeing material, which cost nothing to raise, remain ungathered every year, and are allowed to go to waste, while the United States imports annually more than $5,000,0001 worth of vegetable tanning materials.

Although there would seem to be little excuse for such an uneconomic condition, a study of the situation reveals certain obstacles in the way of making use of this sumac for the purposes to which it is adapted. It is hoped, however, that these difficulties may be overcome by the manufacturers and gatherers if they have a fuller realization of the possibilities of native sumac. The domestic imac industry is well worth organization and development as a

1 Foreign Commerce and Navigation of the United States, 1916, U. S. Department of Commerce.

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means of increasing the present none too plentiful supply of tanning materials, of lessening our dependence on foreign countries, and of giving the people in the rural districts an additional source of income.

Sumac leaves have long been used in tanning leather and in dyeing fabrics. The value of sumac for tanning depends chiefly upon the fact that it yields durable light-colored or white leathers, as a consequence of which it is employed largely in the tanning of bookbinding, glove, and hatband leathers, and for removing darker colored tanning materials from the surface of bag, case, and fair harness leathers. Sumac-tanned leathers have been found to be most durable and suitable for bookbindings and other purposes, where the leather must last indefinitely. The greater part of the gathered American sumac, however, is used in the dyeing of cotton goods.

The sumac industry in the United States is of direct interest to the country people of certain sections. It is largely a rural industry. since the sumac is harvested and cured by the country people and is sold through country dealers for grinding or for the manufacture of extract.

In recent years the quantity of sumac gathered has been much smaller than formerly. Cheaper materials for making lightcolored leathers are in use, while the demands of dyers have not been large. American sumac, owing to careless gathering and curing, yields a darker colored leather than the sumac imported from Sicily, and, since sumac is used for tanning light-colored leathers, this quality renders the American product less desirable and decreases the demand for it. Another reason for the small amount collected is that the gatherers often earned less than could be made at other kinds of work.

While it is true that American sumac, if properly handled, will make an excellent substitute for Sicilian sumac, consumers of sumac must realize that the first step necessary for the production of a high-grade sumac similar to the foreign article is proper gathering and proper curing, which can be accomplished only by offering as an incentive a price commensurate with the labor and the quality of the product. The better the sumac the better should be the price. In this way mutual benefit will be gained and much will be done toward materially developing the domestic sumac industry.

Statistics probably do not indicate accurately the quantity of sumac gathered in the United States, because careful records are not kept by gatherers and dealers of the amounts collected and used. The figures for domestic production given in Table 1 were compiled from the Census reports, and the figures for the imports from the

reports on commerce and navigation of the United States, issued by the United States Department of Commerce.

TABLE 1.-Production of sumac in the United States.

TABLE 2.—Importation of sumac into the United States.

Information in the possession of the Bureau of Chemistry shows clearly that the consumption of domestic sumac during the two or three years prior to 1917 was more than 10,000,000 pounds annually. Early in 1910 domestic sumac was quoted at $55 a ton. In June, 1920, Sicilian sumac was worth about $90 a ton at the chief Atlantic ports, while domestic sumac was quoted at $75 a ton.

SPECIES OF AMERICAN SUMAC.

Important species of sumac growing in North America are: Dwarf sumac (Rhus copallina L.), white sumac (Rhus glabra L.), and staghorn sumac (Rhus hirta (L.) Sudw.). Other species which contain tannin are: Fragrant sumac (Rhus aromatica Ait.), American smoke tree (Rhus cotinoides Nutt.), and coral or Jamaica sumac (Rhus metopium L.). Two species of sumac are poisonous, namely: Poison sumac, or poison elder (Rhus vernix L.), and poison or three-leaf ivy (Rhus radicans L.).

DWARF SUMAC, sometimes called BLACK or MOUNTAIN SUMAC (Rhus copallina).-A shrub or sometimes a small tree with maximum height

of 30 feet and trunk diameter of 10 inches. The leaflets are dark green, smooth on top, paler and often hairy underneath, with edges smooth or few-toothed toward the apex. The fruit grows in dense terminal clusters, is crimson in color, and is covered with fine hairs. The unmistakable characteristics of this species are the winged growth along the leaf stem between the leaflets (Pl. II, A) and the black specks on the new stalk. Dwarf sumac grows in dry soil, and may be found from Maine and southern Ontario to Florida and Texas, and west to Minnesota and Nebraska.

WHITE SUMAC, sometimes called SMOOTH, UPLAND, or SCARLET SUMAC (Rhus glabra).—A shrub, or rarely a small tree, 2 to 20 feet high. The leaflets are dark green on top and whitish underneath, with edges sharply saw-toothed. The fruit grows in dense terminal clusters, and is covered with short reddish hairs. The distinguishing characteristics of this species are the smoothness of the stalks and leaf stems, together with a bluish white bloom, a powdery film similar in appearance to that found on plums, which covers the stalks and the under side of the leaflets (Pl. III). White sumac grows in dry soil from Nova Scotia to British Columbia, and south to Florida, Mississippi, and Arizona.

STAGHORN SUMAC, sometimes called HAIRY SUMAC (Rhus hirta).A shrub, or small tree, with maximum height of 40 feet and trunk diameter of 9 inches. Leaflets, dark green and nearly smooth on top, pale, and more or less hairy underneath, with edges sharply saw-toothed. The fruit, which grows in dense terminal clusters, is thickly covered with bright-crimson hairs. The distinguishing characteristic of this species is the hairy growth along the stalks and leaf stems (Pl. IV). Staghorn sumac is found in dry and rocky soils from Nova Scotia to Georgia, especially among the mountains, and as far west as southern Ontario, Minnesota, Missouri, and Mississippi.

Since poison sumac sometimes is mistaken for the more common species, and its poisonous effects are usually very severe, it seems desirable to describe it as an aid in distinguishing poison sumac from the other species.

POISON SUMAC, sometimes called POISON ELDER (Rhus vernix).— A shrub, or small tree, with maximum height of 28 feet and trunk diameter of 6 inches. The leaflets are green on top and underneath, with edges smooth. The fruit, which grows in loose, open clusters, consists of smooth white or light gray berries. It should be noted that poison sumac differs decidedly from the important species in the color and cluster formation of its fruit. Furthermore, it may be easily distinguished from the dwarf sumac by the absence of the winged growth along the leaf stems, and from the white and staghorn sumac by its smooth-edged leaflets (Pl. V). Poison sumac almost invariably is found in swamps. It grows from southern

Ontario and near the eastern coast in the Eastern and Middle States, south to Florida, and west to Minnesota, Missouri, and Louisiana.

PRESENT METHODS OF GATHERING AND CURING.

COMMON NAMES USED BY GATHERERS.

Sumac is commonly termed by the gatherers either "black" or "white." "Black" sumac refers to dwarf sumac (Rhus copallina), and "white sumac usually means white sumac (Rhus glabra), although it is believed that this term is sometimes applied also to staghorn sumac (Rhus hirta). Staghorn is not so extensively gathered as white sumac. In some sections, as in eastern Virginia, only black sumac is collected, while in others, such as the western part of Virginia and in West Virginia, Maryland, and Pennsylvania, small quantities of white sumac also are gathered.

KINDS AND CONDITION OF SUMAC DESIRED BY EXTRACT MANUFACTURERS.

Dwarf, or black, sumac is the only variety desired by extract makers, other species being refused because, it is stated, they contain a much higher proportion of pithy, milky stalks, and yield less extract. All contracts with gatherers specify that the sumac shall be dwarf, or black, only. The leaves and stems of the sumac alone are of value. The stalk is useless. While small, short new-growth stalks, broken off close below the leaf stem, may be accepted by the buyer, the chances are that they will be refused or received at a reduction in price. Gatherers are advised to take particular pains to see that their sumac contains very little stalk and no berries. Berries are of no value to extract makers.

PROPER TIME TO GATHER.

Extract makers are opposed to the early gathering of sumac, even though the leaves apparently are mature. They state that the leaves gathered in May and June are light in weight, do not yield as much extract, and can not be handled as well in the extracting process. From the viewpoint of both gatherers and extract makers, the best time to gather sumac is in July, August, and September. Gathering should not be done after frost, as the leaves then drop off readily and the color of the extract made from red leaves is darker and less desirable than that made from light-colored, well-cured leaves.

YIELDS PER ACRE.

While sumac is very plentiful, especially in the eastern United States, it rarely covers thickly an area of any extent, but, intermingled with other vegetation, grows rather scattered in patches