205 
drought, poor soil conditions, and atmospheric gases. The 
orway maple se to tolerate congested regions as well as 
any of the s of trees recently planted in New York; and the 
black locust and ailanthus endure the presence of atmospheric 
gases as well as any. The sycamore is also fairly immune from 
troubles common to thickly settled communities e linden 
has the reputation of tolerating mor 1 vere conditions, 
the species kno’ s Tilia platyphyllos being regarded as most 
superior as a shade t 1 
where they are generally affected with frost cracks and are 
usually short-lived 
GEORGE E. STONE 
AMHERST, Mass, 
“NORTH AMERICAN FLORA” 
completion of Volume 9 of North American Flora, ac- 
sentplahel | in October by the siilication of its seventh part, 
is a noteworthy event in the progress of thi rtaking. 
y Dr. W. A. Mu 
butions by Dr. Gertrude S. Burlingham and Mr. 
ennington. The vol i ee t by a bibliography by 
Dr. John H. Barnhart, Bibliograph | indexed. 
memorandum of the history ae this were is not out of place 
t the present time. Publication was commenced in 1905, by 
oO a he coop 
number of experts stationed at other institutions has been ob- 
tained and work at the present time is progressing on about 
