Lower part of an erect 
filament with numerous 
Polysiphonia orthocarpa. 
D. K. D. Vidensk. Selsk. Skr., 7. Række, naturvidensk. og mathem. Afd. VII. 3. 
413 
Thur., to which it seems to be nearly related; but as it differs 
from it by other characters, especially the dimensions of the 
articles, the presence of rhizoids on the erect filaments, and the 
shape of the cystocarps, it seems legitimate to consider it as a 
distinct species. 
The erect filaments issue in great number from creeping 
filaments fixed to the substratum by short rhizoids ending in 
attachment discs. These rhizoids are given off not only from 
the basal but also from the apic- 
al end of the pericentral cells, 
from which they are separated 
by a cell-wall. The articles of 
the creeping filaments are two 
to four times as long as broad. 
Rhizoids are also given off from 
the lower part of the erect 
filaments, but these rhizoids are 
not fixed to any substratum; 
they are of equal diameter in 
their whole length and form 
no attachment disc. They are 
always given off from the un- 
dermost end of the articles, 
often two or three from the 
same article. In rare cases I 
have found them fixed by 
the end to the same filament 
from which they had issued. 
Fig. 353. 
A young and two ripe cystocarps. 107: 1. 
Fig. 352. 
Polysiphonia orthocarpa. Portion of branch 
with tetrasporangia. 
200 : 1. 
