On the PiTHOPHORACEiE. 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 (pi. 1, fig. 8, 18; pi. 4, fig. 7, 8, h). Exceptionall}^, 

 particularly in half-fertile-half-sterile specimens, it takes place, on the 

 contrary, that the upper ()^ounger) branches are stronger developed than 

 the lower (pi. 2, fig. 7, 13). As has already been mentioned above 

 (page 6), these branches, proceeding immediately from the principal fila- 

 ment and being consequentlj^ 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 

 list 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 (pi. 1, fig. 8 c, fig. 18). These 

 new branches, which are of the 2:d degree (pi. 1, fig. 18 6^), are formed 

 exactly in the same manner as those of the firfet, 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. Eoettleri (Roth) nob., the cells in the branches of the 2:d 

 degree have the power of forming new branches (of the 3:rd degree; 

 pi. 1, fig. 18 6^); in all the others they remain unbranched. 



In all the species of Pitlwphora 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 (pi. 1, fig. 8, 13, 18). 

 As a rule, one of two opposite branches is considerably stronger than 

 the other (pi. 1, fig. 8; pi. 2, fig. 7). Neither are they developed at the 

 same time, but the stronger one first, and the feebler one often very 

 much later (pi. 2, fig. 7). 



The cauloïd 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 conirast to the branches, as 

 we remember from the preceding paragraph. Now and then, particularly 



Nova Acta Reg. Soc. Sc. Ups. Ser. III. i 



