AMERICAN SUMAC. 11 



mac leaves and leaf stems, whereas in commercial practice the ex- 

 traction generally is made on the imground leaves and stalks, and 

 consequently is not so thorough, especially in the case of the larger 

 stalks. This practice of making extraction on the unground leaves 

 and stalks undoubtedly accounts for the comparatively high per- 

 centages of potassium oxid in the samples of commercially extracted 

 stalks, analyses of which are given in Table 5. 



Except for the organic matter which it contains, extracted sumac 

 has comparatively little value for the farmer. However, in sections 

 where sumac is gathered, where the land is usually deficient in or- 

 ganic matter, the extracted material can be profitably hauled a mile 

 or two, especially if before scattering on the land it can be mixed 

 and rotted with barnyard manure. 



CAUSES OF POOR QUALITY IN SUMAC. 



Lack of care and attention to details in gathering and curing 

 results in sumac of inferior quality. Undue exposure to the sun, 

 any exposure to dew or rain, heating and molding in deep layers, 

 arid failure to turn once a day while curing cause decided darkening 

 of the leaves and materially reduce the percentage of tannin. The 

 presence of stalks, red leaves, blooms, or berries in cured sumac is 

 objectionable, because they produce an undesirable color on leather. 

 Furthermore, since the stalks contain only about one-fourth as much 

 tannin as the leaves, their presence gives the mixture a lower tannin 

 content. The presence of dirt or sand in cured sumac also is ob- 

 jectionable, for it increases the weight without increasing the tannin 

 content, and leathers tanned with such sumac will darken because 

 of the iron present. 



COOPERATION FOR BETTER SUMAC. 



One of the objects of this bulletin is to point out the necessity for 

 helpful cooperation between gatherers, dealers, and extract makers, 

 with a view to the production of higher grade sumac and sumac 

 extracts and the payment of higher prices to the gatherers for better 

 sumac. This cooperation can be successfully maintained only if it 

 is mutually beneficial. The initiative and success rest with the final 

 buyers, the extract makers, who, by offering a bonus for "extra" 

 quality sumac, can encourage the gatherers to make special efforts 

 to produce a high-grade, bright, clean product. It is suggested 

 that, for the information and guidance of gatherers, dealers and 

 buyers keep on hand suitable samples, one to be known as " Stand- 

 ard," for which they will pay the regular price, and another as 

 " Extra," for which a bonus will be paid. Sumac materially below 



