On THE PITHOPHORACES. 25 
are pluricellular, they increase in the same manner as the principal 
filament apically by the bipartition of the top cell. As a rule the lowest 
(oldest) branches attain the greatest length, and especially the branch 
(or one of the branches, if there are more than one) which is supported 
by the lowest one of the branch-carrying cells, is often found very 
strongly developed (pl. 1, fig. 8, 18; pl. 4, fig. 7, 8, 6). Exceptionally, 
particularly in half-fertile-half-sterile specimens, it takes place, on the 
contrary, that the upper (younger) branches are stronger developed than 
the lower (pl. 2, fig. 7, 13). As has already been mentioned above 
(page 6), these branches, proceeding immediately from the principal fila- 
ment and being consequently of the first degree, are the only ones 
existing in P. sumatrana (v. Mart.) nob. and in fertile specimens of P. 
kewensis nob. and P. Cleveana nob. The cells in the branches of the 
l:st degree are, in these cases, devoid of the power of forming new 
branches. But in the other species, and particularly in sterile specimens, 
the cells in the branches of the l:st degree have the power, partially 
at least, to give origin to new branches (pl. 1, fig. 8 ¢, fig. 18). These 
new branches, which are of the 2:d degree (pl. 1, fig. 18 6”), are formed 
exactly in the same manner as those of the first, and differ from them 
only by having a somewhat smaller diameter of the cells and by a 
feebler general development. Only in one of the known species of 
Pithophora, P. Reettleri (Roth) nob., the cells in the branches of the 2:d 
degree have the power of forming new branches (of the 3:rd degree; 
pl. 1, fig. 18 6°); in all the others they remain unbranched. 
Tn all the species of Pithophora the cells of the principal filament 
possess, at least in the sterile specimens, the power of forming each 
not only one branch, but two, and in P. Roettleri (Roth) nob. even 
three and as much as four. These branches then proceed from the 
mother cell, almost at the same height, and are thus opposite (or 
nearly so) to each other, or placed in a whorl (pl. 1, fig. 8, 13, 18). 
As a rule, one of two opposite branches is considerably stronger than 
the other (pl. 1, fig. 8; pl. 2, fig. 7). Neither are they developed at the 
same time, but the stronger one first, and the feebler one often very 
much later (pl. 2, fig. 7). 
The cauloid of the specimen having in this manner attained its 
full development as to the vegetative organs, the formation of spores 
is commenced in fertile specimens in the manner described above. The 
spores are in general formed basipetally, in contrast to the branches, as 
we remember from the preceding paragraph. Now and then, particularly 
Nova Acta Reg. Soc. Sc. Ups. Ser. III. 4 
