EtTER: PoLYEMBRYONY IN POLYPODIACEOUS FERNS I0I 
old. Several archegonia were open in each instance. After 
eight days the harvesting was done, and Text FIG. 1 illustrates 
one of the results obtained. The smaller embryos were all in 
very good condition but doubtless would have soon succumbed. 
It is especially interesting to note that a, b, and ¢ were closer to 
the sinus than was the dominate sporophyte. This difference in| 
position probably largely accounts for the existence of the 
smaller embryos. 
woth 
fa ps ae b 
\ 4 
f Vc eee 
t ee 
\ 
se vg ee 
ee, os 
/ 4 
’ f 
, “ - 
re . ~ < 
; : } 
ee as d 
Fic. 1. Three embryos and a young sporophyte on a pear prothallium 
of Matteuccia Struthiopteris. a, embryo probably in octant stage; 6, embryo 
two-celled; c, embryo two-celled; d, young sporophyte goat thirty-two 
days old. 
TEXT FIG. 2 is from a gametophyte of Preris longifolia 
with two independent sporophytes. These were fine vigorous 
individuals, well back from the sinus, and distinctly separated 
on the twosides of thearchegonialcushion. Pterislongifolialends 
itself very well to experimentation; it is a vigorous grower, and 
it is not at all surprising that it may bear oie embryos under 
natural conditions. 
To determine just what would happen if a prothallium bearing 
two embryos were halved, several such gametophytes were 
selected from ordinary cultures and carefully divided by 
