Key to the Genera 

 1 . Plant branched _. 2 



1. Plant unbranched OedoPonium 



2. Plant bearing setae with bulbous bases Bulbochaete 



2. Plant without setae; mostly terrestrial " Oedocladium 



BULBOCHAETE C. A. Agardh 1817, p. XXIX 



Thallus a unilaterally branched filament arising from a basal 

 cell which has a holdfast organ (adhesive disc or rhizoidal pro- 

 cesses). Cells cylindrical, ovoid, or rarely repand; usually distinctly 

 larger at the anterior end where, by oblique cell division, a branch 

 may arise; vertical elongation of the plant is accomplished by 

 successive divisions of the basal cell only. Approximately all cells 

 bearing a long seta with a bulbous base, arising obliquely from the 

 anterior end of the cell. Chloroplast a parietal net-work, either 

 dense or loose, covering almost the entire lateral walls. Female 

 reproductive organs (oogonia) swollen ovoid, oblong, or globose, 

 foraied by two divisions of a vegetative cell to produce an outer 

 gametangium and usually supporting suffultory cells, patent or 

 erect; the oogonium surmounted only by a seta, or by a vegetative 

 cell, or an androsporangium; in some species the oogonia sessile and 

 lateral, in all cases, with transverse band-like scars of cell division 

 localized in the median part of the oogonium. Division of the 

 supporting suffultory cell either basal, median, or superior. Male 

 cells either small rectangular cells transformed from the vegetative 

 cells of the female filament, or in dwarf male filaments growing 

 epiphytically on the female plant, having developed from special 

 spores ( androspores ) produced in androsporangia which may be 

 either idio- or gynandrosporous. Oospore usually filling the oogo- 

 nium, the wall of the oospore thick, and usually decorated with 

 pits, areolae, ribs, or reticulations, but smooth in some species. 



The habit of branching and the characteristic bulbous setae 

 make this genus easy of identification. It is desirable to examine 

 many individuals, however, to obtain a complete analysis of the 

 combination of characteristics which define each species. Besides 

 the wall markings of the oospore and the location of the division 

 of the suffultory cell, the range in size of the sex organs, as well 

 as of the oospore and the vegetative cells must be considered. A 

 key to the known species of the region is given below. Attention 

 of the reader is called to the fact that these include only about 

 half of the total species. Reference should be made to the keys 

 in Tiffany (1930, 1937) if plants in question do not readily key 

 out in the scheme used below. 



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