THE FRESH-WATER ALGAE 



I6 7 



230 (221) Zoospores with a circle of cilia near the smaller end. 



Family OEDOGONIACEAE . . 231 



Plants of branched or unbranched filaments, attached in early stages; chromatophore with 

 irregular, linear, or net-like perforations and several pyrenoids; membrane often with transverse 

 stria tions at one end of a cell. Reproduction by means of zoospores with a circle of cilia near 

 the smaller end and by heterogametes. 



231 (232) Plant not branched Oedogonium Link. 



Plants either monoecious or dioecious; in the 

 latter case the filaments bearing antheridia may 

 be normal filaments, or tiny filaments of single 

 cells called dwarf males, attached near the oogonia. 

 These originate from special small zoospores called 

 androspores. But one oosphere hi an oogonium; 

 the spermatozoid enters through a perforation 

 in the wall or through an opening caused by the 

 throwing off of a cap; antheridia single or many 

 together, each containing one or two antherozoids; 

 oospore brown or red. Asexual reproduction by 

 zoospores borne singly in vegetative cells; they 

 have a crown of cilia about a colorless spot at the 

 anterior end. 



Oedogonium occurs in almost all bodies of 

 water and several species are usually found 

 together. 



FIG. 230. Oedogonium crenulato-costatum Wittrock. 



a. oospore. X about 600. b. Oedogonium sp., vege- 

 tative filament, c. division, d. formation of antheridia. 



b, c, d. X about 520. (Original.) 



Btdbochaete Agardh. 



Most of the cells bear- 

 ing a long colorless hair, 

 swollen at the base. 

 Reproduction as mOedo- 

 gonium; the dwarf males 

 very frequent. 



Though not so com- 

 mon as Oedogonium it 

 is found all over the 

 world and sometimes 

 occurs in great quanti- 

 ties, completely cover- 

 ing submerged higher 

 plants with a feathery 

 coating. 



Small branches which 

 have been detached are 

 also often found among 

 other algae. 



FIG. 231. Bulbochaele 

 mirabitts Wittrock. a. 

 Plant with oospore. b. 

 dwarf male on oospore. 

 c. zoospores. X aoo. 

 (Original.) 



