386 



THE NON-VASCULAR PLANTS 



(See Figure 185.} These haustoria penetrate the epider- 

 mal cells of the lilac, and from them absorb food. Since 



the cells of the mesophyll 

 are not injured by it, 

 however, lilac leaves ap- 

 pear to get along pretty 

 well in spite of the mil- 

 dew. Numerous little 

 sporophores arise from 

 the mycelium, and it is 

 the abundance of spores 

 which makes the myce- 

 lium look like dust. 



This fungus, like bread 

 mold, also has a sex 

 method of reproduction. 

 The sex organs are very 

 small, but the structures 

 which result from the sex 

 process are not small. 

 They are big enough to 

 be seen with the naked 



eye. They look like 

 dark-brown dots. They 

 are called ascocarps. 



FIG. 183. Albugo Candida. A kind of para- 

 site (white rust) which attacks members of 

 the mustard family. The figure shows the The outside of them is a 

 appearance of a section of a mustard leaf , . . ., . , , 



cut through one of the parts attacked. Note thick-Walled case, and the 

 the way in which spores are produced. The 

 top row of cells is the epidermis of the host. 

 It is finally ruptured and the spores escape. 

 Note the way in which the hyphae (shaded) growth of the OOSpOre. 

 burrow between the celh ; of the mesophyll F()r ^ oospore 

 and send little suckers (haustoria) into the m ' 



protoplasts. habit we have already 



inside of them is what 

 has resulted from the 



a 



