FRESH-WATER AQUARIUM. 55 



Chara or NileUa, as those plants have no real leaves, but 

 simply stalks in place of them around the stem, iu whorls 

 like the Ccraliqdti/Ium. It is a very graceful plant, and 

 an excellent aerator of the water. I have often used it 

 alone or with Lcmna to stock a tank ; indeed, my first 

 Aquarium was a small jar, with two plants of llornwort, 

 two tad-poles, one small frog, and half a dozen snails. 



The watek-starwokt (CaUitrichc verna) is another class 

 of these useful and, at the same time, ornamental plants for 

 the Aquarium. There is a variety of this species called 

 ylatycarpa-, as well as two other species, C. pedunculate 

 and C. autumnalis, found in the United States. I have 

 been as yet able to find, the water-starwort only in small 

 quantities near New York city, but it is said to be very 

 common in some parts of the State. This plant may be 

 distinguished from its presenting a star of four leaves on 

 the water's surface, of a light green color. A good plan 

 is to throw a rough gathering of this plant into water, 

 and, after well washing it, pull off only the bright green 

 heads with about three or four inches of stalk attached, 

 and cast these into our tank to take their chance ; the 

 plant soon spreads itself over the surface of the water, and 

 gives a healthy green shade that is good for the animals, 

 obstructing the heating rays of the sun. 



Axaciiaris Canadensis (PI. III., Fig. 1), A. alsinastrum, 

 American weed, or, as it has been also called in this coun- 

 try, Udora Canadensis, is one of the most vigorously growing 

 of the aquatic plants that we can introduce into an Aqua- 

 rium, and is, at the same time, extremely common. Mr. 

 and Mrs. S. C. Hall, in their interesting little " Book of the 



