126 FRESH-WATER ALG^E OF THE UNITED STATES. 



CLADOPHORA OLIGOCLONA, Kg. 



Filaments sparingly branched forming pale or dull green 

 mats ; primary branches somewhat dichotomous ; secondary 

 branches often long with short one-celled branchlets ; articu- 

 lations cylindrical, of primary branches 2-6 times as long 

 as broad ; of secondary branches 4-10 times as long. 



Diameter of cells of stems, 40-55 yu. 

 Diameter of branches, 28-40 /*. 

 Stagnant waters. 



Plate CVIII, figs. 1, 2, three short sections of filaments. 



CLADOPHORA FLOTOWIANA, Kg. 



Forms loosely entangled mats ; branches remote dichoto- 

 niose, thin, very long, nearly simple, about 15 // diameter ; 

 frequently at joints, short papilliform, one-celled branchlets. 



Stagnant pond waters. 

 Plate CYII, figs. 7, 8, parts of filaments. 



Very near the preceding (oligocfona), perhaps the same ; 

 Kirchiier has united the two as C. oligoclona. 



CLADOPHORA CRISP ATA, Kg. 



Filaments sparingly branched below, more fully toward 

 the upper ends, insertion, at least of the lower branches, 

 apical 5 cells cylindrical, membrane rather thin, often deli- 

 cately plicate- striate ; cell contents in part disposed in a lax 

 spiral manner ; not observed in older filaments. 



Diameter of lower cells, 40-75 yu. 

 Diameter of branches, 25-30 //. 



Frequent in large floating masses in ponds. 



Var. VITREA, Kg. 



Light green or colorless ; irregularly branched ; cells 6-20 

 times as long as wide. 



Yar. BRACHYCLADOS, Kg. 



Pale green, laxly interwoven ; dichotoniously branched, 

 ultimate branches subulate, patent, mostly unicellular ; cells 

 3-6 times longer than broad. 



Plate CIX, figs. 4-6. C. crispata, var. vitrea; figs. 7-10, 

 var. brachydados. 



CLADOPHORA CANALICTJLARIS, Kg. 



Dichotomously or trichotomonsly branched 5 branches 

 connate at the base, often fasciculately branched above as 



