370 BOTANICAL GAZETTE [November 



Fig. 8. — A mature sporangium showing zoospores differentiated and two 

 papillae of dehiscence. 



Fig. 9. — A stained section of a papilla of dehiscence. 



Fig. 10. — Another section of a papilla of dehiscence, showing the proto- 



plasm and attached inner portion of the plug drawn away from the wall. 



Fig. 11. — Early stages in the development of zoosporangia. 



Fig. 12. — A mature plant, showing the rhizoid system, manner of branch- 

 ing, and arrangement of reproductive bodies. 



Fig. 13.— A mature sporangium discharging its zoospores into a thin 

 vesicle which soon ruptures. 



Fig. 14. — A mature zoosporangium discharging its zoospores without the 

 formation of a vesicle. 



Fig. 15. — Resting sporangium, showing the relative position of the pores 

 in the much thickened wall. 



Fig. 16. — An enlarged portion of the surface of a resting sporangium. 



Fig. 17. — A diagrammatic representation of a microscopic section of the 

 wall of a resting sporangium. 



Fig. 18.— Different stages in the development of the pseudo-septa located 

 at definite constrictions in the hyphae. 



Figs. 19-21. — Microscopic sections through such a septum as shown in 

 fig. 18, a, giving the various appearances that result. 



Fig. 22. 



sporangium 



outer walls cracked open 



? 



inner 



of 



Fig. 23.— A zoospore showing the nucleus with its accompanying mass 

 reserve food material, and two cilia. 



Fig. 24.— Zoospore killed with a 1 per cent solution of osmic acid and 

 stained with Magdala red; the outer portion of the zoospore broke away, 

 leaving the reserve material and nucleus with the single cilium attached. 



Fig. 25. — Zoospore coming to rest preparatory to germination; contraction 

 of the cilium taking place and contents becoming granular. 



Figs. 26, 27.— Early stages in germination of the zoospore: from living 

 specimens. 



Fig. 28.— Section of a young zoosporangium, showing nuclei in division 

 and also several large deeply staining food bodies. 



Fig. 29. 



time 

 preparatory to zoospore 



Fig. 30.— Later stage than that shown in fig. 29: many nuclei more or 



imbedded in the reserve food material; lines of segmentation appearing a 



periphery. 



Fig. 31. — Section of a zoosDoraneium in which s 



place . 



Fig. 32. 



sporangium 



gmentation has taken 



■ 



and a sub-branch. 



Fig. 33 . — Section of a mature resting sporangium. 





