292 



ZYCINEMATACEAE 



PLATE XXIV 



Spirogyra 



Fig. I. — S. velata, spore wall pattern. After Jao. Fig. 2. — S. occt- 

 dentalis, gamctangia and zygospores from Illinois. Fig. 3. — S. lutcospora, 

 zygospore and receptive gametangium from Bohemia. After Czurda. Fig. 4. 

 — S. sulcata, zygospores and gametangia from Wisconsin. After Blum. 

 Fig. 5. — S. obovata, gametangia and zygospores from Szechwan. China. 

 After Jao. Fig. 6. — S. asiatica, zygospore from Tibet. After Czurda. Fig. 7. 

 — 5. lagerheimii, lateral conjugation and zygospore from Sweden. After 

 Wittrock. Fig. 8. — S. tajtiana, gametangia, zygospore, and sterile cells from 

 Texas. After Taft. Fig. 9. — S. perjorans, gametangia and zygospores from 

 Florida. Fig. 10. — S. minutijossa, zygospore and gametangia from Massa- 

 chusetts. After Jao. Fig. ii. — S. porangabae, gametangia, zygospores, and 

 sterile cells from northern Brazil. Fig. 12. — S. skjujae, gametangia and zygo- 

 spores from India. After Randhawa. Fig. 13. — S. hoehnei, gametangia and 

 zygospore from Kentucky. Figs. 14-15. — S. robusta, gametangia and zygo- 

 spores from South Africa. After Nygaard. Fig. 16. — 5. catenaejormis, a not 

 uncommon form of a laterally conjugating filament from Illinois. Fig. 17. 

 — S. scrobiculata, unusual form of receptive gametangia and conjugation 

 through end wall of filament from Illinois. 



