REPETITION AL OR PROLIFER.4TIVE DEVELOPMEST 59 



Amons: filamentous species the sporangia are usuallv formed 

 terminallv, a single sporangium constituting the terminus of the 

 hypha. In Albugo. Svncephalis, and PiptocephaUs the sporangia 

 appear as chains. In Blakeslea the sporangia are aggregated over 

 the surface of the head-like tips of the sporangiophores. 





Fig. 14. Repetitional development among Phycomycetes. A. Repeated 

 formation of sporanaria, each \\-ithin the one previously formed, in Sapro- 

 legnia nwnoica. (After Pringsheim.) B. Sporangia] proliferation to form 

 chains of sporangia in Pytkiimi proliferzcm. (After Butier./ C. Nest-like 

 and chain- 'ike sporangia in Pytbiomorpka gonapodioides. (After Peter- 

 sen.; D. Sporanffium of Peronospori tabacina proliferating to become 

 diminutive sporan^iophore or to form one or more secondar\" sporangLi. 

 £. SporangM renewal in Pkytopktkori palmh-ora from germinating 

 oospore. (After de Bar\-.) F. Proliferation of sporangia in Genaopodyi 



proliferi. 



Re PETITION AL OR PROLIFER.\TrVE DE\TLOPMEXT OF SPORAXGL\ 



AXD SPORES. Sporanoial proliferation is of usual occurrence 

 among certain species of the higher Phycomycetes. It is accom- 

 plished bv seriate formation of sporangia at the apex of the re- 

 productive h\~pha. Proliferation mav be an entirely normal pro- 

 cedure, but in some species it is apparently an abnormality-. By 



