On THE PITHOPHORACEA. 69 
inclosed spores are the greatest of all; they are on an ay. 1% yw. The limits of 
variation are indicated by ‘ 13) 525. 320 U- 
Affinities and Differences. This species is distinguished from its nearest rela- 
tions, P. polymorpha nob. and P. Zelleri (v. Mart.) nob. by considerably greater 
‘dimensions and particularly by a stronger ramification. The cells of the principal 
filament carry here three (or even four) branches in a whorl, and branches of the 
3:rd degree occur regularly. 
Having now described those species of Pithophora which I have seen both in 
a fertile and in a sterile state, it remains to say a few words on a Pithophoraceous 
plant which I know only as sterile. It is the australian Pithophora mentioned above, 
which has been communicated to me by D:r A. GRuNow. According to the infor- 
mation kindly given by D:r A. GRuNOW it has been gathered by D:r E. GRA&FFE 
in two localities, both situated in Upolu, one of the isles of Samoa. One of the 
localities is running fresh water, the other is Mangrove-swamps with slightly brackish 
water on a muddy ground. As the specimens brought from the two localities show 
some small differences, I will describe each local form separately. 
The form brought from the fresh water locality has branches of two 
degrees, which are sometimes placed in pairs opposite to each other, but most fre- 
quently singly. The branches regularly proceed from their supporting cells a small 
space below their top. The thickness of the principal filament varies between 100 
and 110 w, that of the branches of the l1:st degree between 90 and 100 uw, and 
that of the branches of the 2:d degree between 80 and 95 w. The length of the 
common vegetative cells is generally rather considerable. The length varies between 
10—30 times the thickness. In one specimen I have observed cells which very 
strongly call to mind real Pithophora-spores by their very much smaller length, 
their greater thickness and their greater abundance of chlorophyll. The cause of 
my not being able to recognize them as such with certainty is 1:o that the cells 
which ought to be the sister cells of the spores (the subsporal cells) are not parti- 
eularly poor in chlorophyll, 2:0 that the length of the supposed spores varies very 
much, and 3:0 that they have almost all developed (not merely support) branches. 
If they be really spores, they must be supposed to have proceeded in the same 
manner as the spores which I have represented pl. 6, fig. 6, belonging to Pithophora 
oedogonia (Mont.) nob. They would then have germinated while yet remaining 
attached to the mother plant, in the same manner as prolific cells, by bringing 
forth lateral branches. The thickness of those cells varies between 100 and 150 u, 
and their length between 175 and 460 wu. 
The form from the Mangrove-swamps has branches of at least two degrees, 
which are placed singly, opposite in pairs, or now and then three in a whorl. The 
branches sometimes proceed from the supporting cells a small space below their 
top, but often at the very top.!) Most frequently the branch is supported by a 
1) This, together with other things, is the cause why I am not quite convinced of 
this species belonging to the genus of Pithophora. 
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