270 



PLANT STUDIES 



While the ordinary method of reproduction through the 

 growing season is by means of these rapidly germinating 

 spores, in certain conditions a sexual process is observed, 

 by which a heavy-walled sexual spore is formed as a resting 

 spore, able to outlive unfavorable conditions. Branches 

 arise from the hyphse of the mycelium just as in the forma- 



FiG. 236. Mature eporangium of Mucor, showing 

 the wall {A), the numerous spores (C). and 

 the columella (5)— that is, the partition wall 

 pushed up into the cavity of the sporangium. 

 — Moore. 



Fig. 237. Bursted sporangium of 

 Mncor, the ruptured wall not 

 being shown, and the loose 

 spores adhering to the colu- 

 mella.— Moore. 



tion of sporophores (Fig. 238). Two contiguous branches 

 come in contact by their tips (Fig. 238, A)^ the tips are cut 

 off from the main coenocytic body by partition walls (Fig. 

 238, E)^ the walls in contact disorganize, the contents of 

 the two tip cells fuse, and a heavy-walled sexual spore is 

 the result (Fig. 238, C). It is evident that the process is 

 conjugation, suggesting the Conjugate forms among the 



