FAMILY CHARACIOPSIDACEAE 



This family includes attached, unicellular forms which are unable 

 to multiply by cell division in the vegetative state. The plants are 

 variously shaped, ovoid to fusiform or sickle-shaped and are attached 

 by a long or short stipe to filamentous algae or microfauna. The 

 stalk is formed by an extension of the cell wall which consists of but 

 one piece. There are 1 to several parietal, plate-like, yellowish-green 

 chromatophores. Food reserve is in the form of oil. Reproduction 

 occurs by aplanospores, or more frequently by 8-64 zoospores with 

 2 flagella of unequal length. 



Key to the Genera 



Cells ovoid or subglobose, attached by a stipe which usually has no 



basal disc; the stipe longer than the cell body; 1 chromatophore .Peromelia 



Cells fusiform, subcylindrical, or sickle-shaped, attached by a short 

 or long stipe with a basal disc, the stipe shorter than the cell 

 body in most species; chromatophores several (rarely but 1)— Characiopsis 



CHARACIOPSIS Borzi 1894, p. 151 



An attached, ovoid or pyriform, subcylindrical or sickle-shaped 

 cell with a narrow, long or short stipe and usually with a basal 

 attaching disc, growing on filamentous algae or microfauna; chro- 

 matophores 2-5, plate-like, yellow-green bodies; zoospores produced 

 many in a cell, with a single flagellum (probably one long and one 

 very short); gametic union reported for at least 1 species. 



Characiopsis should be compared with Characium, a genus with 

 grass-green chloroplasts and pyrenoids, producing starch and usually 

 having very slender basal stipes. See page 215. Also this genus 

 should be compared with Harpochytrium, certain species of which 

 greatly resemble Characiopsis. Especially when examining preserved 

 algae this comparison should be made. Harpochytrium Hyalothecae, 

 frequently seen in our collections, is illustrated on PI. 93, Figs. 23-25. 



Key to the Species 



1. Cells cyhndrical- C. cylindrica 



1. Cells not cylindrical - 2 



2. Cells with a sharply pointed apex -- 3 



2. Cells with an obtuse apex 5 



3. Cells ellipsoid, with a very short, broad stipe (practically sessile), 



and a short, straight spine-like apex C. spinifer 



3. Cells with a slender stipe 4 



4. Stipe as long or longer than the cell body; 



cell narrowly fusiform C. longipes 



4. Stipe less than the cell body in length; 



cells broadly ellipsoid C. acuta 



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