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 them 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, L.).—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, L.).— 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 AMERICAN SUMAC. 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). Rhus hirta is not so extensively gathered as Rhus glabra. In some sections, as in eastern Virginia, only the dwarf sumac is collected, while in others, such as the western part of Virginia and in West Virginia, Maryland, and Pennsylvania, both dwarf and white sumac are gathered.

KINDS AND CONDITION OF SUMAC DESIRED BY EXTRACT MANUFACTURERS.

In eastern Virginia the dwarf sumac only is accepted, other species being positively refused. All contracts with gatherers specify that the sumac shall be of the dwarf species only. The leaves, leaf stems, and new growth of stalks if broken immediately below the lowest leaf stem are acceptable. The reason given in eastern Virginia for not receiving the white species is that it contains a much larger proportion of pithy, milky stalks, and yields less extract.

In western Maryland, Pennsylvania, and West Virginia, and, in fact, generally in the sections which supply northern mills, the leaves and leaf stems of all varieties, mixed or unmixed, are equally acceptable.

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 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 may be continued until frost. The dropping off of the leaves, however, constitutes a loss, while the color of the extract made from red or poorly cured 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 along old fence rows, and on cut-over and burned-over woodland. Reports have been received that in certain sections it grows thickly, unmixed with other growth, and in sufficient areas to permit cutting with a mowing machine. Several cases of clean stand have been reported, but they have not come directly to the attention of the Bureau of Chemistry. A report has been received from eastern Virginia of a tract of from 10 to 15 acres of burned-over and cut-over land from which 5 tons of dwarf sumac (leaves, leaf stems, and current year's stalk) were gathered. An estimate by the bureau, based on the material gathered from a measured area 20 by 30 feet of white sumac, gave a calculated yield of 4,864 pounds (green weight) per acre. This would give about 1,621 pounds of cured sumac.

QUANTITY A MAN CAN GATHER IN ONE DAY.

Many factors may influence the quantity a man can gather. Some of these are the experience and alacrity of the gatherer, availability or lack of teams for hauling, growth of sumac-whether dense or

scattering species of sumac collected, and whether leaves, leaf stems, and stalks, or only leaves and leaf stems are desired. The amount of sumac collected by one man in one day may weigh from 150 to 600 pounds when dried, but averages between 200 and 300 pounds. From experiments conducted by the bureau, in which the sumac was collected by an experienced gatherer, it has been estimated that the following amounts of sumac (leaves, leaf stems, and stalks combined) can be gathered in one eight-hour day by an energetic man, provided the stand is good, so that little time is lost in going from one patch to another:

Dwarf-728 pounds green; loss of water in curing, 54 per cent; cured sumac, 335 pounds.1

White-1,744 pounds green; loss of water in curing, 67 per cent; cured sumac 576 pounds.

Staghorn-952 pounds green; loss of water in curing, 58 per cent; cured sumac, 400

pounds.

Where the stand is scattering or the gatherer is slow, the quantity gathered will be less, but in no case should an able-bodied man be satisfied with less than 200 pounds of cured sumac (leaves and stalks) from his day's work

GATHERING AND CURING.

The general practice followed in gathering is to break or cut (only the black can be broken readily) the new-growth stalk just below the lowest leaf stem. The sumac is then allowed to wilt in the sun for a few hours or a day, and hauled to a barn, where it is spread on the barn floor in a layer of from 1 to 3 feet in depth, or on racks which permit the circulation of air underneath. The sumac is then turned once or twice each day for a week to aid in the drying and to prevent the leaves from molding. Some gatherers do not let the sumac wilt in the sun, but spread it at once on racks in the barn or under cover. This method aids materially in producing sumac of the lightest and best color.

LOSS IN CURING AND HANDLING.

Experienced gatherers estimate that the green sumac loses from 50 to 60 per cent in weight during curing. There is still further loss in weight between the time of purchase by the dealer and the time of sale, due largely to loss of moisture, still present because of incomplete drying, to falling of leaves, and to the removal of adhering dirt. This loss between the purchase and sale by the dealer varies in amount from 5 to 15 per cent, thus making a total loss in weight from the original green sumac of from 60 to 75 per cent.

Results of laboratory experiments on the curing of sumac (leaves, leaf stems, and stalks) given in Table 3 show losses while curing which agree well with those estimated by gatherers.

1 The dwarf sumac was more scattered than the other two varieties. This may account for the comparatively low figures for this species.

Dwarf..

White.

TABLE 3.-Loss of moisture in curing sumac (collected Sept. 28, 1916).

Staghorn...

There is reason to believe that the loss in curing on the farm is not so great as the loss observed in the bureau's experiments, where the sumac dried out very thoroughly. The total loss in weight of the mixed leaf and stalks from gathering until it reaches the extract maker probably averages very close to 60 per cent.

PREPARATION FOR TRANSPORTATION.

Sumac received by the dealers from the farmers usually comes in bags, or is handled loose in wagonloads like hay, and in many instances may have been hauled as far as 20 miles. Many farmers prefer to deliver the sumac in wagonloads, as they claim that too much time is consumed by putting it up in bags. Since the sumac becomes very brittle when dried and the leaflets are easily broken from the leaf stems, much loss occurs in handling it loose. Dealers, therefore, as a rule, prefer to have the sumac delivered in bags. These bags cost the dealers 8 to 9 cents each, but are usually furnished without cost to the gatherers. Some gatherers, after drying the sumac, flail off the leaves and pack them in bags for shipment. Seventy-five pounds should be packed into a 4-bushel bag, but the average quantity put into them is about 40 pounds.

From the small dealers to the extract manufacturers the sumac is usually handled in bags or bales. The cost of baling is about 10 cents per hundredweight.

PRICES PAID GATHERERS AND DEALERS.

During the seasons of 1916 and 1917 in eastern Virginia the gatherers received from 90 cents to $1 per 100 pounds in trade from the dealers. The extract manufacturers furnished bags for use in hauling and shipping the cured sumac. The dealers received from the extract makers $1.10 per 100 pounds for the bagged or baled material, which in this region includes the new-growth stalks as well as the leaves and leaf stems. In northern West Virginia and western Maryland the gatherers received in 1916 for the leaves and leaf stems alone (no stalks) from 80 cents to $1 per hundred pounds in trade from the dealers, who in turn received $1.10 to $1.15 from the extract makers. In 1917 these prices were about 5 cents per hundred higher. In this section all varieties of sumac are mixed and well packed for shipment in bags furnished free of charge by dealers.

TANNIN CONTENT OF AMERICAN SUMAC.

The leaves and leaf stems together of the three most important American sumacs-dwarf, white, and staghorn-when air-dried, contain approximately the same amount of tannin-that is, from 25 to 35 per cent. The leaves of fragrant sumac are said to contain 13 per cent tannin, of American smoke-tree 21 per cent, and of coral sumac 8 per cent. Usually the quantity of tannin appears to be somewhat greater later in the season than in June and early July. The leaves contain the highest percentage of tannin after they are fully grown and before they begin to turn yellow or red.

Analyses made in the Leather and Paper Laboratory of the Bureau of Chemistry of various samples of sumac gathered in Virginia, West Virginia, Maryland, and Pennsylvania gave the following results:

TABLE 4.-Tannin content of samples of dwarf, white, and staghorn sumac.

Dwarf sumac, it will be seen, contains somewhat more tannin than staghorn or white sumac. This bears out in a general way the statement of buyers in eastern Virginia, though this difference is of itself not great enough to justify the refusal of the white. The sumac samples analyzed were found to average 73.3 per cent leaves and leaf stems and 26.7 per cent stalks. The variation, however, was marked, extending, in the case of the leaves and leaf stems, from 54 to 89 per cent, and, for the stalks, from 11 to 46 per cent. The large proportion of stalks indicated by the percentage last given should never be permitted. Gatherers must be careful to break the stalk close to the lowest leaf stem, and not to gather the long stalk bare of leaves. If the stalks are broken close to the leaf stems, the sumac will usually meet the buyers' demands. Dealers and extract makers very properly insist that the sumac as delivered shall not contain on an average more than 25 per cent of stalks.

The portions of the plant usually considered of value for tanning and dyeing purposes are the leaves and leaf stems, although, as shown in Table 4, the stalks contain from 5 to 10 per cent tannin, an amount entirely too large to discard after the trouble and expense of collecting and hauling to market has been incurred. This tannin should be recovered, as an extract could be made from the stalks

1 These figures apply more particularly to Virginia, West Virginia, Maryland, and Pennsylvania sumacs.