Shaw. — The Fertilization of Onoclea. 271 
started in September were ready for fertilization-experiments 
in the following February, and those started in January were 
sufficiently mature for the same purpose two months after 
the spores were sown. A series of trials showed that when 
female prothallia bearing mature archegonia were placed in 
water, the archegonia opened within five minutes, and when 
male prothallia were present the open archegonia were all 
entered by spermatozoids within three minutes. It was found 
convenient to carefully transfer large numbers of prothallia 
from the soil to the surface of water in watch-glasses. A few 
minutes or an hour later, the prothallia were examined, 
and those with no open archegonia were rejected. Then, 
after the lapse of the desired periods, specimens were taken 
from the watch-glasses and placed in the fixing agent. All 
of the series used, except Series G, were fertilized in the 
manner described. The plants of the latter series, as already 
explained (p. 2 67), were fertilized on the soil and not removed 
until the time for fixing. Unless otherwise specified the 
observations refer to Onoclea sensibilis. In the following 
table of the series of prothallia killed, the italics show the 
material used : — 
isj 
.9 8 
Sowing of culture. 
Series 
Beginning of 
Series. 
Periods between fertilization and 
fixation. 
^ 3 
.y 0 
6 w 
J.S 
w bfl 
u d 
0 w> 
ffi.S 
^ X 
M3 
Sept. ’95 
B 
Feb. 26, ’96 
10, 20, 30 minutes, 1, 2, 3, 4, 
5,0, 8, 10, 12, 14 hours. 
1% 
18-24 
Sept. ’95 
C 
March 4, ’96 
6, 8, 10, 12, 14, 24 hours. 
1% 
24 
Sept. ’95 
D 
March 9, ’96 
1, 2, 3, 4, 5,6, 7, 8, 9, 10 hours. 
1% 
6-8 
Jan. 10-17, ’96 
E 
March 23, ’96 
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 
14, 16, 18, 20, 22, 24, 26, 
28, 30 hours. 
1% 
8-24 
Jan. 10-17, ’96 
F 
April 23, ’96 
1, 2, 3, 4, 5, 6, 8, 10, 12, 14,, 
16, 18, 20, 22, 24, 28, 32, 
36, 40, 44, 48, 60, 72 hours. 
24 
Jan. 10-17, ’96 
G 
May 11, ’96 
h 2, 3 , 4 > 5, 6, 7, 8, 9, 10, 11, 
12, 13, 14, 15 days. 
1% 
24 
