248 THE AMERICAN MONTHLY [Sept., 



pushing the cells apart a little and inserting itself farther and 

 farther from the point whence it started. The hypha? are 

 furnished with minute suctorial organs. These are called 

 "haustoria" (Fig. 15 h). They are globular swellings of the 

 sides of the hypha. They push through the cell- wall and are 

 thus directly surrounded with the living ])rotoplasm of the host. 

 It is through the haustoria that the parasite does the injury 

 which it inflicts, as well as by the presence of the mycelium in 

 any of the organs of the host. An examination of its floral organs 

 will often demonstrate the presence of the mycelium in these 

 delicate and very im2)ortant parts of the host. The fructifying 

 organs of Cystopus are of two sorts. There are first and more 

 commonly the aerial hypha? and their conidia. These are 

 formed on hyphse which burst through the sides of the host giv- 

 ing rise to the blisters or scales already referred to. The conidia 

 germinate on the surface of the host, and send down a hypha 

 through the stoma among the intercellular spaces of the host to 

 reach the succulent cells below. The second mode of develop- 

 ment is the sexual one> It is a similar mode to the conjugation 

 of Mucor. In it, two sorts of cells are formed on hyphje located 

 among the mycelium. One of these is smaller than the other. 

 It is called the antheridia. It is the male element in the sexual 

 process. The other cell is larger and spherical. This is met 

 in the host tissues by the antheridium and the two fuse as 

 shown in Figure 15. The product of this act is a cell called 

 the oosphere. The oosphere is now said to be " fertilized," and 

 it now developes into motile swarm-spores like those of the 

 conidia in appearance. These require the death and decay of 

 the host to enable them to develop and produce their genera- 

 tion. 



4. — Other Fungi. 

 It is not within the scope of this article to do more than to 

 awaken an interest in these very easily accessible microscopical 

 subjects. It is worth while, however, in closing, to say that 

 these little beings, are from their immense productivity and the 

 power of drawing their sustenance from other animals and 

 plants, capable of being of great service or harm to man. In 

 the case of the fungi, a majority are probably harmful rather 

 than useful. There are the rusts, the moulds, the smuts, which 

 annually do immense harm to crops; then, there is a fungus 



