Postelsia 
0 
Isat 
TS 
a region 10 centimeters long which is sterile 
except for a few small dots of fertile tissue, 
and distal’ to this “there is: the second@ssonms 
which is more irregular in outline and measures 
1ox2 centimeters. One might suppose from 
this specimen that we have here a regular 
succession of sori of different ages from the 
base to the tip, which renders fruiting contin- 
uous. But I think that such is not the case 
in Renjrewia for ,this. 1s-a single: specmuen 
among more than a hundred examined. and 
the few small dots of fructiferous tissue be- 
tween the two sori seem to indicate that instead 
of two distinct sori, we have only an unusual 
case of irregularity. Moreover, as nearly as 
can be determined without sectioning, for the 
specimen seems too valuable to mutilate, both 
of the patches are of the same age. 
Because of the low level at which it erows, 
juvenile forms are difficult to obtain and the search 
made for them was rather meagerly rewarded. 
A complete series was not found, the smallest 
being 5 centimeters long with others larger 
connecting with the mature forms. Since the 
