81 
a name unconditionally preoccupied. Rhus hirta (L.), to be 
legitimately written only for our Sumach, has never been pro- 
posed, and is not a synonym in fact—Rhus hirta (Harv. Mss. in 
Herb. Kew), Engler, 1. c. is. 
Moreover, in maintaining Rhus hirta (L.) for the Staghorn 
Sumach, we follow the ornithologists’ interpretation of ‘Once a 
synonym always a synonym.” 
I should, therefore, propose that Rhus typhina, L. (1760) be 
replaced by Rhus hirta (L.) (=—Datisca hirta, L., 1753), not 
Rhus hirta (Harv. Mss. in Herb. Kew), Engler (1883). 
: Geo. B. SUDWORTH. 
Forestry Division, Department of Agriculture, Washington, D. C. 
[Mr. Sudworth’s notes touch on the question of what impor- 
tance is to be placed on the publication of a name as a synonym. 
His first-mentioned species appears to have been first alluded to 
In print by Torrey and Gray (FI. N. A. i. 217, 1838), where it 
was doubtfully referred to the European R. Cotinus, L., and “R. 
cotinoides, Nutt. in herb. acad. Phila.,” printed as a synonym. — 
The appearance of this name dates then from 1838, and we fail 
to see any reason why it should not be maintained. It is quite 
equivalent to an author publishing two names for a plant, the 
first of which is preoccupied. / His second case is similar, but not 
identical. Rhus tridentata, Sond., should in my view not stand, 
n account of the earlier publication of Rhus tridentata, Thunb., 
which would bring in R. hirta, Harv., for R. tridentata, Sond. 
——N..L. B.} 
Notes on Peronosporacee. 
__ The following list of Peronosporacez includes species found in 
the vicinity of Brookings, S. D., during the summer of 1891. 
The region covered is that included within a radius of five miles 
from the city. Specimens of all the species have been collected 
upon the college farm, also, which lies close to the city and is 
Situated upon prairie uplands. ‘ ae 
PERONOSPORA ARTHURI, Farlow. 
_ This species was very plentiful during July on Cnothera 
biennis. Plants growing in the wild flower garden suffered most. 
Many plants were entirely stripped of their leaves. 
