CLADOPHORA AND VAUCHERIA 185 



267. They are typically aquatic, green plants (holo- 

 phytes), but many have become parasites or saprophytes, 

 and suffered degradation into " fungi" (hysterophytes). 

 The number of species now known is about 1260. The 

 holophytes are readily separated into two classes, the 

 Lower Tube Algae (VAUCHERIOIDEAE) and the Higher 

 Tube Algae (BRYOPSIDOIDEAE), and from the first have 

 been derived a considerable number of hysterophytes 

 which may be separated as a class of Tube Fungi, or 

 Lower Fungi (PHYCOMYCETEAE). 



268. Water Flannel (Cladophora) is one of the com- 

 monest genera of the Lower Tube Algae, occurring in 

 large tangled masses of stout branched fila- 

 ments in fresh-water streams, or even in 



salt waters. Its coenocytes have thick 

 walls, with two to many nuclei. In their 

 propagation and generation they so closely 

 resemble Ulothrix and Microspora that they 

 were formerly included in the same family. ciadophora. 

 Zoospores with two or four cilia escape 

 from the segments and after a free-swimming period 

 come to rest and grow directly into new plants. Like- 

 wise biciliated isogametes issue from similar segments, 

 and fuse into zygotes. 



269. The Green Felts (Vaucheria) are good repre- 

 sentatives of one of the families in which the plant body 



is a continuous coenocyte. They are 

 coarse, green, tubular, branching and 

 rooted plants which grow in abun- 

 dance on the moist earth in the vicinity 

 S.G.76.-vaucheria. of springs, and in shallow running 

 water, forming dense felted masses. 



270. They propagate by large compound motile zoo- 

 spores, formed in the ends of the branches. Each zoo- 



