268 ZYC;.\HMATACEAE 



PLATE XII 



ZVGOGONIUM, PlLURODISCUS, MoLGhOTIOPSIS, AND DiBARYA 



Figs. 1-5. — Zygogoniutn sincnsc, zygospores, vegetative cells, partheno- 

 spores, lateral conjugation, and resulting zygospore; also remnants of 

 sporangium wall after escape of zygospore; details of spore wall. Figs. 6- 

 8. Z. exuvielUjorme, zygospores formed by lateral and scalaritorni con- 

 jugation, and details of spore wall, from Colombia, South America. After 

 Jao. Figs. 9-11. — Z. plaf{ountiosporum, zygospores formed by lateral and 

 scalariform conjugation. Note bilateral asymmetry of spore wall markings 

 from Colombia, South America. After Jao. Figs. 12-15. — Pleurodiscus 

 borinqmnae , vegetative cells with disc-shaped chromatophores; zygospores 

 and details of sporangium and spore walls from Puerto Rico. .After Tirfany. 

 Figs. 16-17. — Mougeotiopsis calospora, vegetative cells with chromatophores 

 in different positions; zygospores with characteristic deep pits in the spore 

 wall from Latvia. After Skuja. Figs. 18-19. — Debarya glyptosptrma, 

 arched gametangia and zygospores from Sweden. Figs. 20-21. — D. acl{lcy- 

 ana, face and side views of zygospores from Michigan. Figs. 22-23. — D. 

 costata, zygospores in face and side views from Fyzabad, India. Figs. 24- 

 26. — D. polyedrica, zygospores and gametangia from Yunnan, China. After 

 Skuja. Figs. 27-28. — D. smithii, vegetative cell and mature zygospore; 

 lower figure shows growth of the two chromatophores and the multiplica- 

 tion of pyrenoids during the early stages of conjugation, from Fresno, 

 California. Figs. 29-30. — D. hardyi, conjugating gametangia and immature 

 spore; cannot be placed in this genus with certainty until mature zygospores 

 are lound. 



