13 



Bibliographical Notes on well known Plants.— X. 



By Edward T.. Greene. 



Rhus Canadensis, Marshall, Arb. 129 (1785). 



Rhus aromatica. Ait. Hort Kew. i. 367, and 



RJiiis siiaveolens. Ait. 1. c. 368 (1789). 



Bctula tripJiylla, Thunb. Diss. Betul. 12 (1807). 



Although Marshall's descriptions are never clearly diagnostic, 

 still, in the case of this Rhus it would seem as if no American 

 botanist could doubt for a moment what bush the man had in 

 view. But the name has always been placed in the synonymy 

 of R. aromattca sometimes with, — as often without — a mark of 

 doubt. At the time of his writing there was no other known 

 North American shrub to which his description would apply ; 

 and there is no excuse for our continuing to employ the later 

 name R. aromatica, Thunberg's grave error in referring the 

 bush to the genus Bctula, is not more remarkable than that of 

 his master Linnaeus,' when the latter, as some critics assure us, 

 first publislied his Rhus typJiiua as a species oi Datisca {D. hirta, 

 Linn. Sp. PI. 1037). 



That Aiton's R. aromatica and R. suavcolcns are one and the 

 same species has long been admitted on all sides ; the two names 

 are about equally good, and the uniform retention of the first 

 rather than the second is one of many cases in which authors 

 have, with one consent, recognized the principle of priority of 

 place. 



* 



There was an earlier Rhus Canadensis of Philip Miller, and 

 this, in days long past, may have stood with some people in the 

 way of the adoption of that of Marshall. But Miller's name is 

 conceded to be a synonym either of R glabra or R. typhina. 

 It was a pinnate-leaved species, at all events, and a mere synonym, 

 and cannot therefore stand in the way of the restoration of R, 

 Cajiadcnsis, Marsh. * 



♦In the deep canons of Northern Arizona whicli lead down to the Grand Canon 

 of the Colorado, I discovered a few months since an exceedingly interesting shrub 

 which will bear the following name and description : 



Rhus Canadensis^ Marsh,, var, SIMPHCIFOI.IA. Shrub 3 or 4 feet high, diffuse, 

 slender ; leaves an inch long or less, round-ovate, obtuse, nearly truncate at base, 

 coarsely and somewhat evenly crenate, rarely with a very small lobe or separate 

 leaflet on one side below ; spikes few flowered, almost capitate. 



