swelling and gelatinization of the old cell membrane, which pushes 

 the daughter cell forward, so that protoplasts are always located at 

 the distal ends of these mucilaginous stalks. Pascher (1937-1939) 

 favors the placing of this family in the Heterococcales, mostly on 

 the basis of cell arrangement and the absence of the copious gela- 

 tinous investments that characterize the Heterocapsales. As he also 

 states, this family is one of several whose position in the Heterokon- 

 tae is uncertain. Additional information is needed before a satisfac 

 tory taxonomic disposition can be made. 



MISCHOCOCCUS NaegeH 1849, p. 82 

 Characteristics as described for the family; plant an attached, 

 usually dichotomously branched, gelatinous tube inclosing globular 

 cells which are often distantly removed from one another, or are 

 in 2's and 4's in the distal end of the tubes; chromatophores 1-4, 

 parietal, pale yellow-green discs; asexual reproduction by aplano- 

 spores or by uniflagellated zoospores; sexual reproduction by iso- 

 gametes has been reported. 



Mischococcus confervicola Naegeli 1849, p. 82 

 PI. 93, Fig. 30 

 Characteristics as described for the genus; tubes dichotomously 

 or tetrachotomously branched, with 1 or 2 globose cells in the distal 

 end of each cylinder; cells 3.5-5.5/* in diameter. 



Adhering to filamentous algae or entangled in the mixture of 

 vegetation in shallow water of bays and small ponds. Wis. 



ORDER HETEROCOCCALES 

 Unlike the Heterocapsales, these plants are permanently non- 

 motile in the vegetative state and can assume motility only through 

 the formation of zoospores. The plants are mostly unicellular (or 

 may form colonies incidentally, as in some species of Ophiocytitim ) . 

 In one family, Gloeobotrydaceae, small colonies occur. Although 

 mostly free-floating, a few forms are definitely epiphytic, or other- 

 wise sedentary. The chromatophores are 1 to many, parietal, ovate or 

 irregular plates, and oil and leucosin occur as food reserves. Repro- 

 duction, as far as is known definitely, is non-sexual, autospores and 

 zoospores being used, although reports of gametic union have been 

 made. 



Key to the Families 

 1 . Plants attached 2 



1. Plants not attached 3 



2. Plants attached by a stipe or with a broad adhesive base — 4 



2. Plants sessile, adhering without differentiation of the cell wall 3 



[347] 



