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.) 



2 39 ( 2 35) Plant epiphytic adhering throughout to other plants. . . . 240 



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



Herposteiron Nageli. 



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 

 Aphanochaete, but the name Herposteiron seems to 

 have priority. 



FIG. 235. Herposteiron con/ervicola Nageli. X 4So. (After Hazen.) 



