335 



of the filaments. A branchlet is given off from each segment so, that 

 they are placed alternately on both sides of the median line of the 

 main branch forming in this 

 way two series on both sides 

 of it upon the dorsal side 

 of the branch (Fig. 336 a). 



The branchlets tend to- 

 wards the top (Figs. 334, 

 335a) issuing from the mother 

 branch with acute angles; 

 they are monosiphonous, 

 unbranched and, when fully 

 developed, composed of long 

 cylindrical cells about 20 f.i 

 thick and often more than 

 10 times as long, only taper- 

 ing slightly towards the 

 summit. The whole branchlet 

 reaches a length of about 

 1200 u. The basal cell in the 

 branchlets is short, nearly 

 quadratic, and becomes more 

 or less immersed in the cor- 

 tical layer ; the summit of the 

 branchlet is obtuse. The 

 branchlets are rather persi- 

 stent ; in the older, lower part 

 of the filaments they are 

 dropped, leaving only the 

 basal cells. 



At some distance from 

 the summit when the branch- 

 letb are already much devel- 

 oped the adventitious bran- 

 ches with continuous growth 

 are formed (Figs. 334, 335 a). These contribute to the ramifica- 

 tion of the plant and are issued now and then without any more 

 definite distance between them. They are mostly issued at the side 

 of a branchlet (Fig. 335 c). I have most frequently found them placed 



Fig. 334. CoUoniclla arcuntu nov. spec. 



Upper parts of filaments. 



(About 45:1). 



