188 



CHrPTOGAMS 



the chief clanger which besets all very small organisms 

 exposed in the air, namely, drying. Where the Fungus 

 spreads away from the bread along the bottom of the 

 dish, it is seen that the sporangial stalks arise in groups 

 at points where the h3'pha3 touch tlie dish, at whicli 

 points also rootlike organs appear (whence the name 

 Rhizopus, root footed). The whole has very much the 

 habit of a Strawberry plant propagating by runners 

 (Fig. 303). 



A B 



iOi> (TPunmitidU o£ 307. Conjugation of Rhizopus: A,B, C, 1), suc- 



the spore. eessive stages in the production of tlie 



zygospore. 



447. Under certain conditions short lateral branches 

 spring out near one another from neigliboring Ii3'ph8e and 

 grow until their tips are in contact (Fig. 307). The 

 end parts of the Ijranches become cut off by septa. They 

 are the <jametes. which fuse after tlie walls have been 

 aljsorbed at the point of contact. The result is the 

 formation of a thick-walled resting spore, or zygospore 

 (Fig. 307. z). 



Water Molds ( Saprolegniaceae) 



448. The Ijest Avay to secure material for the study of 

 these plants is to bring in a large handful of decaying 

 leaves from some pond hole or bog wliere water stands, 

 throw them into a jar of water, and after them throw in 

 either dead insects or succulent slioots of seedlings killed 

 by heat. Upon these food materitils the spores of the 

 Water ^Molds from the dead leaves will fasten and ger- 



