Vol, 46: No. 12 
BULLETIN 
OF THE 
TORREY BOTANICAL CLUB 
DECEMBER, I919 
Preliminary notes on the embryology of Reboulia hemisphaerica 
WILLIAM L. WooDBURN 
(WITH PLATE 19) 
The object of this paper is to present a part of a more extended 
study on the embryology and cytology of Reboulia hemisphaerica 
(L.) Raddi. Only certain stages in the process of fertilization and 
in the early development of the embryo sporophyte will be con- 
sidered at this time. The description of various other stages in 
the life history together with a summary of the previous literature 
on Reboulia will be left for a subsequent report. 
FERTILIZATION 
The male gamete in the bryophytes may undergo two series 
of marked morphological changes. The first series includes the 
steps leading from the non-motile condition of the androcyte 
(the cell which directly becomes transformed into the mature 
sperm) through the formation of the actively motile free-swim- 
ming sperm. The second series includes the reverse steps and 
occurs in those cases where a sperm reaches an egg. In this 
second case the motile sperm becomes again non-motile with a - 
resting nucleus similar to that of the androcyte or androcyte 
mother-cell. Details of the main stages in the first series have 
been carefully described for numerous liverworts and mosses. 
€ processes accomplished in the second series, after the sperm 
reaches the egg, are not so well known. However, soon after 

[The ButteTin for November (46: 423-460. pl. 17, 18) was issued December 8, 
1919.] 
461 
