Sentence:  A great revolution is about to be witnessed in this tanning and dyeing material. Supplies have commenced to arrive from Virginia, United States, the quality of which is the best that has ever reached Great Britain. [...] In common fairness it must be added, however, that the very "worst" tests of the American are superior to the "best" of the Sicilian; this includes not only the <WSD>sumacs</WSD> of Virginia, but those of Maryland, Tennessee, &c. [Quoting Alexander Mcrae.] 
Meaning of the word marked with <WSD> tags:  (sense 2)Dried and chopped-up leaves and stems of a plant of the genus "Rhus", particularly the tanner's sumac "(see sense 1)", used for dyeing and tanning leather or for medicinal purposes.