giving the sporangium the appearance of being bounded by as many 

 as 4 cells. Zygospore wall smooth or variously decorated; with 

 residues in the gametangial cells outside the zygospore. 

 The genus should be compared with Debarya. 



Key to the Species 



1. Reproduction by aplanospores only; conjugation 



and zygospores unknown M. ventrtcosa 



1. Reproduction by conjugation; aplanospores present or absent 2 



2. Zygospores formed in the tulae, but extending into and 



dividing one of the gametangia 3 



2. Zygospores formed wholly in the tube, or extending into 



both gametangia _ " 



3. Zygospores drum-shaped ( short-cylindric ) M. varians 



3. Zygospores some other shape, globose, triangular, or ovate 4 



4. Zygospores triangular to quadrangular-ovate in face view M. abnormis 



4. Zygospores some other shape j j 



5. Zygospores globose or triangular-ovate, 30-40u in diameter M. floridana 



5. Zygospores ovate to subglobose, 40-45m, in diameter M. sphaerocarpa 



6. Zygospores formed wholly in the conjugating tube 7 



6. Zygospores extending into and dividing both gametangia 22 



7. Zygospore wall smooth ° 



7. Zygospore wall (median or outer layer) decorated 17 



8. Vegetative cells 20— 40w in diameter 9 



8. Vegetative cells 20m in diameter or less 13 



9. Spore wall blue M. maltae 



9. Spore wall brown ; 1^ 



10. Zygospores cylindric-ovate in front view M. laetevirens 



10. Zygospores some other shape 11 



11. Zygospores ovate, 40-48u in diameter M. Hirnii 



11. Zygospores some other shape • 12 



12. Zygospores quadrately ovoid to subglobose, 30-40^ in 



diameter ^- genuflexa 



12. Zygospores ovate-globose, (23)-30-31m in diameter M. scalarts 



13. Zygospores globose 1^ 



13. Zygospores quadrate-globose or rhomboid 16 



14. Vegetative cells 6-12/x in diameter M. parvula 



14. Vegetative cells larger 15 



15. Spore wall blue; vegetative cells 17-20-(22)m in diameter M. maltae 



15. Spore wall brown; vegetative cells 12-18w. in diameter M. recurva 



16. Zygospores quadrate-globose or rhomboidal; 



aplanospores oblique-ovate ^- Reinschii 



16. Zygospores sexangular- or octangular- globose; 



aplanospores globose ^- calcarea 



17. Vegetative cells 8-16/* in diameter M. nummuloides 



17. Vegetative cells (14)-18-20m in diameter 18 



18. Zygospore wall punctate 1^ 



18. Zygospore wall scrobiculate 21 



19. Spore wall blue, finely punctate M. cyanea 



19. Spore wall brown, coarsely punctate 20 



[298] 



