COLEOCHMTE. 113 



ming around it passes down the tube of the oogonium and fertilizes the 

 egg. 



263. Sporocarp. — After tlie egg is fertilized the cells of the threads near 

 the egg grow up around it and form a firm covering one cell in thickness. 

 This envelope becomes brown and hard, and serves to protect the egg. This 

 is the "fruit" of the coleocliEEte, and is sometimes called a sporocarp 

 (spore fruit). The development of the cell mass and the zoospores from the 

 egg has been described abovei 



Some of the species of coleochsete consist of branched threads, while others 

 form circular cushions several layers in thickness. These forms together 

 with the form of our plant C. scutata make an interesting series of transi- 

 tional forms from filamentous .structures to an expanded plant body formed 

 of a mass of cells. 



