VOLUME XXVI NUMBER 1 
BOTANICAL GAZETTE 
FULLY. B66 
ON THE LEAF AND SPOROCARP OF PILULARIA. 
DuNCAN S. JOHNSON. 
(WITH PLATES I-III) 
Durinc the course of some work on the development of the 
foliar structures of Warsilia guadrifolia L., the results of which 
have been published elsewhere (’98), a brief examination was 
also made of the same structures in the related Pilularia. Cer- 
tain features observed here suggested the desirability of making 
a more careful study of the latter genus, and following out in 
detail all stages of the development for comparison with the 
same stages in Marsilia. 
Through the kindness of Professor Eugenius Warming, Dr. 
Ostenfeld Hansen, of Copenhagen, collected for me in July 1897 
a considerable quantity of fruiting material of Piluaria globuli- 
fera L. With this material the work embodied in the present 
paper has been prosecuted at the biological laboratory of the 
Johns Hopkins University, while holding the Adam T. Bruce 
fellowship for 1897-8. 
The material was fixed in 95 per cent. alcohol, which seemed 
to give very good results except in the older stages, where the 
preparation of certain tissues of the capsule for the gelatiniza- 
tion, which causes the bursting of the capsule, had already 
begun. In this stage the sporocarps were often considerably 
shrunken, as happens in Marsilia after using other fixing agents 
unless great care is used in running up through the alcohols. 
