LESSONS IN BOTANY. 195 



a vigorous growth of Mould. When these are full grown, some 

 of the spores may be sown on a piece of moistened bread, 

 which, under a glass will soon develop a fine crop of Mould. 

 The moulds do not contain chlorophyll and are saprophytes, 

 living upon decaying vegetable or animal matter, or they are 

 parasitic. 



With the moulds, spirogyra and water net are associated des- 

 mids which are found abundantly in shallow fresh water, and 

 diatoms which occur in both salt and fresh water, often forming 

 a thin yellowish layer at the bottom of the water. These forms 

 of life are beautiful and interesting objects of study, but their 

 minute size makes their observation difficult. This group of 

 plants is called ZYGOPHYTA,from the fact of their forming a zygo- 

 spore or yoke spore. The plants of this group differ considerably 

 among themselves but are similar in their modes of reproduction, 

 but not alike, as in some cases the spores have organs of locomo- 

 tion while in others they do not have them. Yet in this respect 

 this class is clearly superior to the protophyta. 



The next division of plants is called OOPHYTA, egg-spore-plants. 

 The distinguishing characteristic of the plants of this group 

 is that they develop special cells which contain one or more 

 rounded masses of protoplasm which are fertilized by the con- 

 tents of another special cell of smaller size, which results in the 

 production of an oospore from which a new plant may be de- 

 veloped. 



In streams and ponds tufts of da,rk green plants may be seen 

 floating in the water from stones or sticks or other objects to 

 which they are attached. These masses of vegetable matter are 

 probably the simple or branching filaments of some species of 

 (Edogonium. These plants multiply by the sexual process of re- 

 production as above, and by an asexual process as well. 



The Vaucheria is another member of this division of plants. 

 It forms dense felt-like masses in water, or on damp ground or 

 rocks. They do not have the slippery feel of spirogyra but 

 change to a dingy color at the fruiting stage and the filaments 

 are coarse enough so that many things can be learned about 



