11-22/1 long. Filaments very long. Chloroplast a perforated plate, 

 sometimes densely padded, forate. 



Common in swamps and in soft water lakes; intermingled with 

 other algae and seldom found in pure growths. Mich., Wis. 



ORDER CYLINDROCAPSALES 



In this order there is a single family, Cylindrocapsaceae, with 

 CyUndrocapsa as the only genus. The architecture is essentially 

 filamentous with ovoid or oblong cells in uniseriate arrangement, but 

 there is a frequent tendency toward pahnelloid conditions with bi- 

 seriate or irregular arrangement. The cells may be adjoined in pairs, 

 or separate and evenly spaced within a lamellated gelatinous sheath, 

 with concentric cellulose layers around each cell. The chloroplast 

 is a massive, dense body without pattern and often obscured by 

 starch grains. There is 1 pyrenoid. Sexual reproduction is oogamous. 

 The oogonia are enlarged cells inclosed by much swollen walls, and 

 usually occur in the same filament with the antheridia, which are 

 smaller, somewhat quadrangular, cells arranged in double series, 

 with two antherozoids being produced in each cell. These enter the 

 oogonium through a pore in the thick wall of the female organ. 

 Both sex organs are red and are in marked contrast to the dense 

 green of the vegetative cells. Asexual reproduction is by biflagellate 

 zoospores which in their germination form an attached filament. 

 Upon ageing, the filaments become free-floating and are usually 

 found entangled among masses of other algae. 



The form of the chloroplast and the oogamous type of reproduction 

 may be interpreted as characters so distinctive as to exclude CyUn- 

 drocapsa from the Ulotrichales, where it usually is classified. 



FAMILY CYLINDROCAPSACEAE 



CYUNDROCAPSA Reinsch 1867, p. 66 

 Plants short unbranched filaments of oblong, ovoid, or quadrate 

 cells, uniseriate ( rarely biseriate or palmelloid ) in arrangement and 

 inclosed by a wide, tough gelatinous sheath with distinct lamella- 

 tions about the individual cells. Chloroplast (1 to each cell) a 

 massive, dense body containing a central pyrenoid. Filaments 

 attached when young by the adherence of the mucilaginous tube 

 to the substrate. Enlarged oogonial cells occur in the same filament 

 as the antheridia, or in separate filaments. 



Key to the Species 



Cells quadrate or quadrangular-ovate, 20-26ai wide C. conferta 



Cells oblong or ovoid, up to tvdce their diameter 



in length, 12-18^ vi^ide C. geminella 



[109] 



