Fig. 346. 
Polysiphonia urceolata. a, 
portion of female plant. 
b, young procarp-bearing 
trichoblast. 220 : 1. 
ae 
B 3:1. 
410 
is usually curved so that the spor- 
angia are placed in a row at the 
convex side. When trichoblasts are 
present, the sporangia are placed to 
the right of the foregoing trichoblast 
(fig. 348 A). The sporangia-bearing 
joints have 6 pericentral cells. In the 
trichoblast-bearing shoots a small 
peripherie cell is further cut off at 
the base of the joint; in the joint next 
to a trichoblast this cell is situated 
immediately to the right of the tricho- 
blast. In spore-bearing shoots without 
trichoblasts such a small peripheric 
cell was not cut off (fig. 348 B). 
In a female plant with fully devel- 
oped eystocarps containing apparently 
= IR, 
I 
& 
SC 
nn 
Ic 
ec 
ie 
JOO) 
SOC 
Q “4 
(ea) 
Fig. 347. 
Polysiphonia urceolata. 
cystocarp. 68:1. 
normal carpospores, sporangia were here and there met with 
in the filaments. The sporangia were developed in the usual manner (without form- 
ation of a small peripheral cell) but they were small and undivided and obviously 
abnormal. A very remarkable case is shown in fig. 349. A trichoblast has produced 
an aborted procarp in its second joint but has then over it been transformed into 
a sporangia-bearing shoot, with incompletely developed sporangia. The third joint 
Fig. 348. 
Polysiphonia urceolata. A, portion of tetrasporiferous branch with trichoblasts. 
B, portion of tetrasporiferous branch without trichoblasts. C, transverse sec- 
tion of tetrasporiferous joint after evacuation of the telraspores. D, transverse 
section of a sterile joint of the same branch, with five pericentral cells. 
A, C, D 200 :1. 
Fig. 349. 
Polysiphonia urceolata. A female 
trichoblast has been transformed 
from the fourth joint into a 
tetraspore-bearing branch. 
150 :1. 
