THE FRESH-WATER ALGAE 



169 



238 (236, 237) Lateral branches in whorls or tufts, smaller than the main 

 axis Draparnaldia Bory. 



Plant attached by a disc of cells. Terminal cells usually ending in a long, colorless hair. 

 Reproduction by means of zoospores with four cilia and a pigment spot. No fertilization 

 known. 



In Draparnaldia the photosynthesis takes place principally in the tufted branches, as the 

 chloroplast of the principal axis is reduced to a small, equatorial band in each cell. 



All forms of Draparnaldia are large and are found in much the same localities as the larger 

 forms of Myxonema. 



Fig. 234. Draparnaldia plumosa Agardh. X about 50. (Original.) 



239 (235) Plant epiphytic adhering throughout to other plants. 



240 



240 (241) Plant 01 irregularly branched filaments, setae or hairs not abundant. 



Herposteiron Nageh. 



Plant small, cells with a parietal chromatophore, a 

 pyrenoid, and frequently a long colorless hair; re- 

 production by means of egg-shaped zoospores, with 

 four cilia and a pigment spot, two spores being formed 

 in a single cell. 



This is of frequent occurrence on other filamentous 

 algae but usually occurs only as small isolated in- 

 dividuals. 



It has long been included under the name of 

 Aphanochacte, but the name Herposteiron seems to 

 have priority. 



Fig. 235. Herposteiron confervicola Nageli. X 450. (After Hazcn.) 



