A CONTRIBUTION TO THE LIFE HISTORY OF 
QUERCUS. 
CONTRIBUTION FROM THE HULL BOTANICAL LABORATORY. 
ABRAM H. CONRAD. 
(WITH PLATES XXVIII AND XXIX) 
THE material for this study was all collected in the vicinity 
of the University of Chicago in the spring and summer of 1898. 
Gatherings of several species were incidentally made, but Quercus 
velutina Lam. (Q. coccinea tinctoria Gray ) afforded the most com- 
plete series, and as my investigations have been devoted chiefly 
to this species, it is alone considered in this paper. 
In dealing with material so refractory as Quercus one seldom 
secures a satisfactory series during a single season of collecting. 
The difficulties to which I here refer are due in part to the stub- 
bornness with which the material resists the penetration of fixing 
agents, and in part to the remarkable uniformity with which any 
stage occurs in all the ovules at the same time. This bars one 
from an opportunity of retrieving any loss from the mismanage- 
ment of a batch of material. Detailed cytological observation 
has not been attempted, the object having been rather to deter- 
mine the nature, order, and time of events as they occur in the 
gametophyte generation. 
Except the brief account of Quercus by Miss Benson in her 
work on the Amentacez, I have no knowledge of any attempt 
to work out the life history of the genus. 
The work was done under the guidance and encouragement 
of Dr. John M. Coulter and Dr. Charles J. Chamberlain, to whom 
my thanks are due. 
MATERIAL AND TECHNIQUE. 
During late winter and early spring collections were made at 
intervals of several days, with a view to determine the stage of 
408 [JUNE 
