CHAPTER RIGHT 



THE GENUS DEBARYA WITTROCK 1872 



Wittrock established the genus Debarya better to classify the 

 Mougeotia glyptosperma, so lucidly described and figured by 

 Anton de Bary in 1858. Since then several other species have been 

 discovered w^ith similar characteristics. The filaments are simple, 

 made up of cells two to twenty diameters long with ribbonlike, or 

 platelike, chromatophores with several distinct pyrenoids arranged 

 either in a single row, or scattered. The nucleus is centrally 

 located in the cell and attached to the side of the chromatophore. 

 The Debaryas resemble the Mougeotias during the vegetative 

 phase. 



They differ from the Mougeotias, however, during the repro- 

 ductive phase. At the beginning of conjugation, or during aplan- 

 ospore formation, the reproductive cells become filled with a cel- 

 lulose colloid deposited as successive layers inside the cell walls. 

 Moreover, there are no cytoplasmic residues left in the gametangia 

 outside the spore walls. Conjugation is scalariform, and the gam- 

 etes unite in the conjugating tubes (isogamous). Aplanospores, 

 parthenospores, and akinetes have been observed in 2 of the 

 species. 



The zygospores are compressed-spheroid, ovoid, or quadran- 

 gular-ovoid. The spores of 4 of the species are distinctly tricari- 

 nate, with an equatorial and two lateral keels. The median walls 

 may be further ornamented with pits, radial ridges, and undu- 

 lations. 



All the 6 species are exceedingly rare, but they have been col- 

 lected in Europe, Asia, North America, and New Zealand; they 

 are probably more widely distributed than is surmised at the 

 present time. 



Several of the species that were formerly described as belong- 

 ing to this genus have now been placed in the genera : Mougeotia, 

 Mougeotiopsis, Zygnemopsis, and Hallasia. 



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