Fig. 275. 
Seirospora Griffithsiana. Upper end 
of shoot, from Frederikshavn (6361). 
300 : 1. 
Fig. 276. 
A—C from Tonneberg Banke; A, upper end of 
shoot with spirally arranged branches. B, two branches are borne on the 
same joint. C, lower part of stem with cortication. D, hyaline hair. A, B 200:1. 
C 70:1. D 350:1. 
Seirospora Griffithsiana. 
348 
had a spiral with changing direction and 2 had irregu- 
larly arranged branches. The ramification is often pseudo- 
dichotomous in the upper parts of the shoots, the bran- 
ches being of the same dimensions as the mother shoot 
and the latter changing direction by each branch (fig. 
276 A). In a specimen from Tonneberg Banke I once 
found two vegetative branches of equal size on the 
same joint, diverging from each other at a right angle 
(fig. 276 B), and in the disporangia-bearing region of a 
specimen from the same locality I repeatedly found two 
branches on the same joint arranged now side by 
side, now one under the other or obliquely under the 
other (fig. 279). Even three branches were found on 
the same joint, one of which, however, was probably a 
young sporangium. The two branches were never opposite. 
Hyaline hairs do not usually occur. Only in speei- 
mens from the harbour of Frederikshavn thin hyaline 
hairs were not rarely met 
with at the end of the 
branches (fig. 276 D). 
As shown by ScHMITZ 
(1893, p. 277), all the cells 
contain a single nucleus. 
The usual thallus cells con- 
tain numerous chromato- 
phores which may be rather 
long (fig. 279 B). 
Plants with sexual or- 
gans have not been met 
with in the Danish waters. 
For these organs see the 
quoted papers by BoRNET 
et THURET and Scumirz. 
On the other hand, dispo- 
rangia, tetrasporangia and 
paraspores were found. The 
specimens from Herthas 
Flak were sterile, those from 
the Samsø area bore only 
paraspores. The specimens 
from Frederikshayn, which 
were fairly numerous, bore 
