54 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull. 



The Cladophoraceoe secrete very little or no mucus, and 

 are, therefore, a resting place for epiphytes. 



Key to Genera. 



i. Filaments unbranched; cells often slightly swollen 



Chcetomorpha 



Filaments commonly branched ; cells not swollen ... 2 

 2. With branched rhizoids Rhisoc Ionium* 



Without rhizoids Cladophora* 



Description of Genera. 



Chaetomorpha Kiitz. Wide, simple filaments of thick- 

 walled, swollen segments ; fixed at the base, the basal segments 

 being shorter than the rest. The cell wall is firm and lamellose. 

 Mostly marine or in brackish water. 



Rhizoclonium Kutz. Filaments slightly branched, with 

 branched rhizoids at the base ; articulate, somewhat contorted, 

 having here and there short branches composed of from one 

 to three cells. 



[R. lacustre forma Americanum Wille ; R. hieroglyphicum 

 var. macromeres Nordst.] 



Cladophora Kiitz. Filaments much branched, the last 

 branches much thinner tnan the main stem ; cell walls thick, 

 cells longer than broad. Propagation by zoogonidia, which 

 develop in large numbers within the cells. 



C. glomerata (L.) Kutz., Fig. 274. 



[C. callicoma Kiitz.] 



ORDER VII. SIPHON ALES. 



Plant composed of an elongated ccenocytic filament (cceno- 

 cyte), which is much branched. The order inhabits salt water 

 almost exclusively. The only family living in fresh water is 

 the Vaucheriacece. 



FAMILY I. VAUCHERIACE/E. 



Thallus elongated, somewhat branched, ccenocytic, usually 

 attached. The protoplasm contains many minute nuclei. The 

 oval chloroplasts are small and numerous. The cell wall is 

 thin and easily broken ; after which the injured part is cut off 

 by a septum, and the uninjured parts develop into new plants. 



