82 ZYGNEMATACEAE 



2^^i in thickness. In a few species with quadrangular spores, 

 pectose layers arc formed between the sporangium wall and the 

 spore. Most species have yellow to brown spores; 8 species have 

 blue spores. 



Only during the reproductive phases of the life cycle can 

 species of Debarya and Temfiogametum be separated with cer- 

 tainty from those of Moitgeotia. 



Many of the published figures of Mougeotias do not show 

 cytoplasmic residues in the gametangia after union of the gam- 

 etes, because they are of little or no significance in the identifica- 

 tion of species. However, they are present in all species of the 

 genus now known. 



The generic names formerly applied to certain species of 

 Mougeotia include the following: Sphaerocarpus Hassall 1843; 

 Mesocarpus Hassall 1845; Pleurocarpus Braun 1855; Staurosper- 

 mum Braun 1855; Craterospermum Braun 1855; Plagiospermum 

 Cleve 1868; Sphaerospermum Cleve 1868; Gonatojiema Wittrock 

 1878. Czurda 1932 included among the Mougeotias certain spe- 

 cies here classified in the genera: Debarya, Mougeotiopsis, and 

 T emtio gametum. 



Key to the Species of MOUGEOTIA 



I. With zygospores (rarely aplanospores also present) 2 



I. With aplanospores (zygospores rare or unknown) 69 



2. Sporangium between 2 undivided gametangia 3 



2. Sporangium dividing i of the gametangia 45 



2. Sporangium dividing both gametangia 48 



3. Sporangia globose, subglobose, ovoid, ellipsoid or dolioform, 



longer axis parallel with the conjugating tube 4 



3. Sporangia cylindric-oblong with concave sides and rounded 



ends 35 



3. Sporangia with longer axes at right angles to the conjugating 



tubes 38 



4. Spore wall smooth 5 



4. Spore wall not smooth 22 



5. Diameter vegetative cells usually less than 24^4 6 



5. Diameter vegetative cells usually more than 24 /a 17 



6. Vegetative cells usually less than 12/i in diameter 7 



6. Vegetative cells usually between 12^ and 24A1 in diameter 11 



7. Spores globose 8 



7, Spores ellipsoid or ovoid, longer axis same as that of tube 10 



