196 PRACTICAL LESSONS IN SCIENCE. 



them from observation with the naked eye. In studying the 

 vaucheria during the fruiting stage, it will be found interesting 

 to observe them carefully several times during the day, especially 

 late at night, and early in the morning. 



Other members of this group are the seaweeds, Fucus and Sar- 

 gassum. They grow from just below low- tide to just above high- 

 tide, and often attain great size. They are washed ashore in 

 great quantities during storms, and are much used for manure, 

 and from their ashes Iodine and Bromine may be obtained. 



The CARPOPHYTA or spore-fruit-plants are distinguished by the 

 formation of a sporocarp as the result of the fertilization of the 

 female element. The sporocarp usually consists of a fertile part 

 which produces spores, and a sterile part, so formed as to inclose 

 the fertile portion. The spores are not the direct but a secondary 

 result of the fertilization. The plant body usually has a more 

 perfect development than in the previous divisions. 



To this division belong the large and interesting class of sea- 

 weeds called Florideae, which are noted for their delicate forms 

 and rich coloring. They are mostly of a red color, due to a pig- 

 ment soluble in cold fresh water. The color varies through every 

 shade of red from bright rose to purple. Irish moss used for 

 making blanc mange is one of the best known. 



To this division also belong a great group of parasitic plants 

 or fungi, and while they are too minute for detailed study, yet 

 their presence in patches on plants and something of their effects, 

 their color, their changes when fruiting, etc., are interesting sub- 

 jects of study. A species occurs on the leaves of the apple and 

 cherry, another on the leaves of the willow; another on the 

 leaves of the grape, doing much injury, is called Oidium Tuckeri. 

 One occurs on the leaves of the maple and a very common spe- 

 cies is found on the leaves of the lilac. They occur on the leaves 

 of the oak, elder, mandrake, pea, and many other plants. 



In the study of these fungi or mildews, or any other plant, it 

 is interesting to watch several plants of the same species through 

 the whole growing season, noting all changes, so as to get some 

 idea of the life history of the plant. By watching several plants, 



