AQUATIC PLANTS USEFUL TO THE MICROSCOriST. 49 



ance of the following forms, he need have no trouble in 

 learning their names, although he may not have studied 

 botany ; he has only to compare the leaves with the 

 figures in this chapter. It is, of course, understood that 

 there are many aquatic plants not here referred to, only 

 those being included in this list which afford the most 

 certain supply of microscopic life. The leaves of many 

 water-plants fall against the stem and cling together 

 when lifted into the air ; but if the student will place a 

 small part of the plant in a saucer ("individual" butter 

 dishes are good for this purpose), he can float them out 

 against the white surface and so compare them with the 

 figures. 



RANUNCULUS AQUATILIS (Fig. 6). 



A part of the stem and a single leaf of this plant are 

 shown about natural size in the figure (Fig. 6). It is 

 quite common in ponds and 

 slowly flowing streams: The 

 leaves are dissected into fine, 

 rather stiff and hair -like parts, 

 to which many minute animals, 

 such as Rotifers (Chapter VIIL), 

 Vorticellas (Chapter V.), and 

 Stentors (Chapter V.) are fond 

 of attaching themselves. The 

 leaves are placed above each 

 other on opposite sides of 

 the rather brittle stem, and usually quite wide apart. 



Fig. 6. Leaf of Ranunculus 

 nqndtilis. 



