1889.] Botany. 26$ 
the mode before explained/ as soon as the barberry foliage 
is ready, test the germination power of the P. graminis by 
placing a few fragments in water in a watch-glass. If it ger- 
minate freely and produce a good crop of mycelical spores, as 
proved by microscopic examination, the contents of the 
watch-glass may be at once employed. It is best to do your 
infection experiments in the evening. Water one of the bar- 
berries freely, through the nose of a watering-can, and then 
cover it with a bell-glass ; then water the outside of the bell- 
glass. By so doing, the temperature of the enclosed air is 
reduced, and the inside of the bell-glass, as well as the leaves 
of the barberry become bedewed with condensed vapor. 
After leaving it a few minutes, remove the bell-glass and ap- 
ply the germinating spores with a camel-hair pencil. As the 
promycelial spores easily become diffused in the water in the 
watch-glass, by stirring it with the camel-hair pencil the 
water becomes equally charged with them ; then by simply 
brushing the water on the leaves you may be pretty sure of 
successfully infecting the plant. Replace the bell-glass and 
give it another douching outside with the watering-can. If 
sufficient material has been prepared, each alternate barberry 
may be infected in the same manner. The bell-glass need 
not be kept over the infected plants more than two or three 
days. If the weather be very bright, the bell-glasses should 
be shaded by putting a piece of matting or carpet over them 
to prevent the foliage being scorched by the sun. In the 
course of eight or ten days the yellow spots, on which the 
spermogonia are produced will appear, and in two or three 
weeks the perfect aecidiospores will be developed. It will 
then be seen that only those barberries to which the spores 
were applied have the scidiospores on them^ while the alter- 
nate plants remain free. If an attempt be made to infect a 
plant in the daytime, when the sun's rays are full upon it, it 
will be found that the water all runs off the leaves ; but by 
operating in the evening, in the manner directed, the leaves 
are bedewed with a thin layer of moisture, and no difficulty 
Will be found in applying the spore-charged water. — C. B, 
Plowright, in Monograph of UredinecE and Ustilaginece. 
A True Field Manual of Botany.— The publishers 
announce that they will bring out an edition of the new revi- 
sion of " Gray's Manual," with narrow margins, and with limp 
cover binding, for field use. As this will bring the book 
and kept out of doors during the winter, so^thTthey may be subjected to the same 
vicissitudes of temperature and moisture as would happen to them in a state ot 
