rate, it would take only two or three trees to evaporate a whole 
barrel of water a day. On the other hand, the evaporation from 
cacti and such desert plants is so small as to be very difficult of 
measuring. We are uncertain as to what advantage this evapora- 
tion may be to the plant; but we do know that the water coming up 
from the roots serves the useful purpose of bringing to the leaves 
the minerals which they need for helping to make the living sub- 
stance and other complex chemical compounds there manufac- 
tured. 
Food manufacture in green plants is a most important pro- 
cess. The farm crops of the United States manufacture every 
year, by means of sunshine and the green coloring matter in their 
leaves, food materials worth $3,000,000,000. This seems all the 
more incredible when we reflect that it takes nearly 50 square 
yards of green leaf surface to make a pound of starch in a work- 
ing day of 10 hours. 
E. W. O. 
PLANTS NOW BLOOMING 
Near the southern end of the local flora valley and at the 
northern end of the lake are large masses of the mountain laurel 
(Kalmia latifolia). Its splendid masses of bloom will be at their 
finest during the present week. The Latin name of this plant 
commemorates the fact that this beautiful shrub was first dis- 
covered by Peter Kalm, an early traveller in America, who sent 
the specimens to Linnaeus, who named the plant Kalmia. 
N. T. 
NOTICE 
The Brooklyn Botanic Garden (of the Brooklyn Institute of 
Arts and Sciences) is open free to the public daily, from 8 a. m. 
until sunset ; on Sundays and holidays at 10 a. m. Entrances on 
Flatbush Avenue, opposite Prospect Park; on Washington 
Avenue, south of Eastern Parkway; and on Eastern Parkway, 
between the Museum building and Prospect Heights reservoir. 
A docent will meet parties by appointment and conduct them 
through the Garden. Telephone, 6173 Prospect. 
Additional copies of this and preceding Leaflets may be had 
on request by mail or otherwise. 
