10 BOTANICAL GAZETTE [JULY 
simultaneously in multitudes of neighboring superficial cells, so 
that thousands of filamentous gametangia are produced, covering a 
considerable area of the surface of the thallus. 
The nucleus of the female gametangium initial increases greatly 
in size, like that of the male, and becomes larger than the vegetative 
nucleus. The chromatin of the nuclear reticulum gradually in- 
creases and finally there is organized a prophase with 22 chromo- 
somes (fig. 10, a) anda 
single nucleolus. The 
nuclear membrane 
either persists or dis- 
appears at the time of 
the organization of the 
equatorial plate (fig. 10, 
Fic. 7.—Mature male gametangia: a, cross 0,¢). The centrosome- 
section; b, tangential longitudinal section; c,optical like structures at the 
section viewed laterally, in which red pigment spots 
have developed in a part of the plastids closely P oles are present only 
associated with each nucleus, during metaphase and 
early anaphase. At telo- 
d, and no central spindle 
laid down by the coopera- 
rmation of cytoplasm. 
cellular stage, whether male 
the visible structure and size 
e in the size of the male and 
gametangia have reached the 

; in the former cas 
fig. . : c 
(fig. 15, 6), and in the latter it remains composed of > cells (fig. 15, ¢). 
