80 
-ording to Engler’s division, the combination remains unchanged; 
but if Cotinus is made a section of Rhus, Cotinus Americanus, 
Nutt. becomes R. Americanus (Nutt). (=R. cotinoides, Nutt. 
MSS. in Herb). 
The name Rhus cotinoides, by which this plant has long been 
designated, is commonly attributed to Nuttall; the latter, how- 
ever, first applied it only as an herbarium name. It is said, 
moreover, to have been first published in 1860 (Chapman's Fl. 
Southern States); but the name doubtless belongs to Cooper, 
who published it in 1859 (Rep. Smithsonian Institution for 1858, 
250), citing as a synonym, Cotinus Americanus, Nutt., which is 
equivalent to a formal publication. 
Rhus typhina, L..(1760).—Dr. Britton has discussed (Bulls 
Torr. Bot. Club, xvii. 269) the synonymy of this plant, and 
points out that the first name, Datisca hirta, L. (Species Plan- 
tarum, 1037, 1753), which is commonly cited as a synonym of 
this plant, is debarred as the original name for the Staghorn 
Sumach, because of Engler’s publication (DC. Monog. Phan. iv. 
425, 1883) of the combination Rhus hirta, Harv. (Mss. in Herb. 
Kew) as a synonym of Rhus tridentata, Sond. Dr. Britton’s de- 
cision would seem to be in strict accordance with the principle to 
be observed, “ Once a synonym always a synonym.” 
But in following this principle to the letter, perhaps the fun- 
damental meaning is overlooked. It is true that 1883 marks the 
first appearance of the binominal Rhus hirta (Harv. Mss. 
Herb. Kew), Engler, and would thus appear to preclude the use 
of this name for our Staghorn Sumach. But before holding fast 
to this position, we must, it seems to me, inquire whether the 
specific term /ér¢a—unquestionably first applied to our plant—c4? 
be lawfully appropriated in any other combination than in one 
for our species, This term is doubtless the permanent member 
of the binomial to designate our Sumach, and in whatever genus 
the species is finally placed, its original specific name Airia—™ 
not antedated by an earlier application to another species—must 
belong where first applied.- Hirta, therefore, never was 4 8Y™ 
onym, nor can it ever become one; and in forming from Datisca 
hirta, L., the combination Rhus hirta, Harv. |. c. for an Africa? 
species of Rhus (R. tridentata, Sond.), an invasion was made i 
