iyo 



GREENE 



between northern New England and the headwaters of the 

 Mississippi beyond Lake Superior ; another species or two pecu- 

 liar to that vast empire of the Middle West, the prairie country ; 

 as many more in that different and equally extensive stretch of 

 country lying between southern Missouri and the shores of the 

 Gulf of Mexico. Then, since there is a Rhus glabra all up and 

 down the two thousand miles' length of the Rocky Mountain 

 region, this ought to be thoroughly distinct by plenty of charac- 

 teristics, and to resolve itself naturally into a number of varieties 

 or subspecies. Just the same should be looked for in the shrub 

 accredited to another empire, that of the Pacific slope northward 

 lying between the sources of the Columbia and Puget Sound; 

 while the scores of isolated mountain ranges rising up out of the 

 deserts of Nevada, Utah, Arizona and New Mexico — for the 

 type in question is there also — should furnish another and pre- 

 sumably the most marked group of Rhus glabra segregates. 



Our herbaria cannot to-day be supposed to be well supplied 

 with specimens representing this type. No author has investi- 

 gated it, and no special call has been made for the collecting of 

 these shrubs from different regions. Nevertheless, the mass of 

 material that has been before me during some months past is 

 amply sufficient to enable the investigator to point out characters 

 by which a number of species may be, and reasonably must be, 

 given recognition ; characters of foliage in abundance, and 

 characters of the fruiting panicle and the fruit itself. 



Perhaps more trying than the task of examining and com- 

 paring specimens to find out specific characters, is the great 

 amount of bibliographic work that is necessary in order to 

 determine which one of the several eastern species ought to 

 bear the name Rhus glabra; for even this, as indicated — 

 though never described — by Linnaeus was an aggregate. In 

 the botanic gardens of Europe several species had been long in 

 cultivation, had been recognized as species and even described 

 as such, when Linnaeus in the middle of the eighteenth century 

 came along, and, bundling all the glabrous kinds together, named 

 not any one of them, but the whole bundle of species, Rhus 

 glabra. 



If Linnaeus is to be credited with some one particular Rhus 



